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Vesper HW, Smith SJ, Audain C, Myers GL. Comparison study of urinary pyridinoline and deoxypyridinoline measurements in 13 US laboratories. Clin Chem 2001; 47:2029-31. [PMID: 11673372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Harata N, Ryan TA, Smith SJ, Buchanan J, Tsien RW. Visualizing recycling synaptic vesicles in hippocampal neurons by FM 1-43 photoconversion. Proc Natl Acad Sci U S A 2001; 98:12748-53. [PMID: 11675506 PMCID: PMC60125 DOI: 10.1073/pnas.171442798] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exo-endocytotic turnover of synaptic vesicles (SVs) at synapses between hippocampal neurons in culture was examined by electron microscopy (EM). We carried out photoconversion (PC) of the fluorescent endocytotic marker FM 1-43 by using 3,3'-diaminobenzidine to convert the dye signal into an electron-dense product. Electron-dense products were located almost exclusively in SVs, whose densities were bimodally distributed in two sharply demarcated populations, PC-positive (PC+) and PC-negative (PC-). The median densities of these populations did not vary with the proportion of vesicles stained within a presynaptic terminal (bouton). The proportion of PC+ SVs remained constant across consecutive thin sections of single boutons, but varied greatly from one bouton to another, indicating marked heterogeneity in exo-endocytotic activity. Our experiments indicated that only a minority of SVs were stained in most boutons after stimuli known to cause complete turnover of the functional vesicular pool. A direct spatial correlation was found between FM 1-43 fluorescent spots seen with light microscopy and PC+ boutons by EM. The correlation was clearer in isolated boutons than in clusters of boutons. Photoconversion in combination with FM dyes allows clarification of important aspects of vesicular traffic in central nervous system nerve terminals.
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Micheva KD, Holz RW, Smith SJ. Regulation of presynaptic phosphatidylinositol 4,5-biphosphate by neuronal activity. J Cell Biol 2001; 154:355-68. [PMID: 11470824 PMCID: PMC2150764 DOI: 10.1083/jcb.200102098] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol 4,5-biphosphate (PIP2) has been implicated in a variety of cellular processes, including synaptic vesicle recycling. However, little is known about the spatial distribution of this phospholipid in neurons and its dynamics. In this study, we have focused on these questions by transiently expressing the phospholipase C (PLC)-delta1 pleckstrin homology (PH) domain fused to green fluorescent protein (GFP) in cultured hippocampal neurons. This PH domain binds specifically and with high affinity to PIP2. Live confocal imaging revealed that in resting cells, PH-GFP is localized predominantly on the plasma membrane. Interestingly, no association of PH-GFP with synaptic vesicles in quiescent neurons was observed, indicating the absence of detectable PIP2 on mature synaptic vesicles. Electrical stimulation of hippocampal neurons resulted in a decrease of the PH-GFP signal at the plasma membrane, most probably due to a PLC-mediated hydrolysis of PIP2. This was accompanied in the majority of presynaptic terminals by a marked increase in the cytoplasmic PH-GFP signal, localized most probably on freshly endocytosed membranes. Further investigation revealed that the increase in PH-GFP signal was dependent on the activation of N-methyl-D-aspartate receptors and the consequent production of nitric oxide (NO). Thus, PIP2 in the presynaptic terminal appears to be regulated by postsynaptic activity via a retrograde action of NO.
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Lund JN, Scholefield JH, Grainge MJ, Smith SJ, Mangham C, Armitage NC, Robinson MH, Logan RF. Risks, costs, and compliance limit colorectal adenoma surveillance: lessons from a randomised trial. Gut 2001; 49:91-6. [PMID: 11413116 PMCID: PMC1728357 DOI: 10.1136/gut.49.1.91] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND AND AIMS In the USA and many other countries, endoscopic surveillance of colorectal adenoma patients is now widely practised. However, the optimal frequency and mode of such surveillance are not yet established. The aim of this trial was to compare surveillance at one, two, or five year intervals using either flexible sigmoidoscopy or colonoscopy. METHODS Analysis of a randomised trial of flexible sigmoidoscopy and colonoscopy over one, two, or five years after stratification for "high" or "low" risk of recurrent adenomas. The trial started in 1984. RESULTS A total of 776 patients were stratified into "high" (n=307) and "low" (n=469) recurrence risk groups and randomised to flexible sigmoidoscopy or colonoscopy at varying intervals. Only 81 recurrent adenomas (30/81 were >1 cm in diameter) were detected in the 2307 person years of follow up within the surveillance study. Adenoma recurrence was significantly higher in the high risk group (relative rate 1.82; 95% confidence interval 1.2-2.9) but recurrence rates per 1000 person years were low and not significantly different in those surveyed by colonoscopy or flexible sigmoidoscopy. Loss to follow up was greatest in those having an annual examination compared with two or five yearly surveillance examinations. Despite surveillance, invasive cancer developed in four patients compared with an expected value of 9.12 for the general population in England (p=0.10); of these four patients who developed cancers, only one was detected by surveillance examination. CONCLUSIONS Adenoma recurrence rates were much lower than expected in both high and low risk groups. This suggests that endoscopic surveillance should be targeted at high risk groups. A surveillance interval of five years was as effective as shorter intervals in terms of cancer prevention, and was associated with similar compliance to two yearly examinations.
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Moyer ES, Smith SJ, Wood GO. Carbon tetrachloride replacement compounds for organic vapor air-purifying respirator cartridge and activated carbon testing--a review. AIHAJ : A JOURNAL FOR THE SCIENCE OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH AND SAFETY 2001; 62:494-507. [PMID: 11549144 DOI: 10.1080/15298660108984652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
This article reviews efforts by researchers and organizations around the world to identify chemicals as substitutes for carbon tetrachloride in measuring activated carbon activity (adsorption capacity) or organic vapor air-purifying respirator cartridge (or other packed carbon bed) breakthrough times. Such measurements usually are done to determine if a minimum performance standard is met. Different criteria have been established, supporting data developed and used, and conclusions reached. This article presents relevant published, unpublished, obscure, and recalculated data which the reader can use to make a choice of replacement chemical and testing conditions. No recommendations for a specific replacement chemical are endorsed or promoted in this review.
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Singer C, Blankstein E, Koenigsberg T, Mercado C, Pile-Spellman E, Smith SJ. Mammographic Appearance of Axillary Lymph Node Calcification in Patients with Metastatic Ovarian Carcinoma. AJR Am J Roentgenol 2001; 176:1437-40. [PMID: 11373209 DOI: 10.2214/ajr.176.6.1761437] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE We describe the mammographic appearance of axillary lymph node calcification in three patients with metastatic ovarian carcinoma. CONCLUSION Axillary lymph node calcification may be identified mammographically in patients with metastatic ovarian carcinoma and may be evidence of unsuspected metastatic disease. The pattern of calcification differs from that seen with metastatic breast carcinoma.
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Airlie J, Baker GA, Smith SJ, Young CA. Measuring the impact of multiple sclerosis on psychosocial functioning: the development of a new self-efficacy scale. Clin Rehabil 2001; 15:259-65. [PMID: 11386395 DOI: 10.1191/026921501668362643] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To develop a scale to measure self-efficacy in neurologically impaired patients with multiple sclerosis and to assess the scale's psychometric properties. DESIGN Cross-sectional questionnaire study in a clinical setting, the retest questionnaire returned by mail after completion at home. SETTING Regional multiple sclerosis (MS) outpatient clinic or the Clinical Trials Unit (CTU) at a large neuroscience centre in the UK. SUBJECTS One hundred persons with MS attending the Walton Centre for Neurology and Neurosurgery and Clatterbridge Hospital, Wirral, as outpatients. METHODS Cognitively impaired patients were excluded at an initial clinic assessment. Patients were asked to provide demographic data and complete the self-efficacy scale along with the following validated scales: Hospital Anxiety and Depression Scale, Rosenberg Self-Esteem Scale, Impact, Stigma and Mastery and Rankin Scales. The Rankin Scale and Barthel Index were also assessed by the physician. RESULTS A new 11-item self-efficacy scale was constructed consisting of two domains of control and personal agency. The validity of the scale was confirmed using Cronbach's alpha analysis of internal consistency (alpha = 0.81). The test-retest reliability of the scale over two weeks was acceptable with an intraclass correlation coefficient of 0.79. Construct validity was investigated using Pearson's product moment correlation coefficient resulting in significant correlations with depression (r= -0.52) anxiety (r =-0.50) and mastery (r= 0.73). Multiple regression analysis demonstrated that these factors accounted for 70% of the variance of scores on the self-efficacy scale, with scores on mastery, anxiety and perceived disability being independently significant. CONCLUSION Assessment of the psychometric properties of this new self-efficacy scale suggest that it possesses good validity and reliability in patients with multiple sclerosis.
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Nicolai J, Smith SJ, Keunen RW. Simultaneous side effects of both clozapine and valproate. Intensive Care Med 2001; 27:943. [PMID: 11430560 DOI: 10.1007/s001340100937] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Miller AJ, Cookson SJ, Smith SJ, Wells DM. The use of microelectrodes to investigate compartmentation and the transport of metabolized inorganic ions in plants. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:541-549. [PMID: 11373303 DOI: 10.1093/jexbot/52.356.541] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microelectrode measurements can be used to investigate both the intracellular pools of ions and membrane transport processes of single living cells. Microelectrodes can report these processes in the surface layers of root and leaf cells of intact plants. By careful manipulation of the plant, a minimum of disruption is produced and therefore the information obtained from these measurements most probably represents the 'in vivo' situation. Microelectrodes can be used to assay for the activity of particular transport systems in the plasma membrane of cells. Compartmental concentrations of inorganic metabolite ions have been measured by several different methods and the results obtained for the cytosol are compared. Ion-selective microelectrodes have been used to measure the activities of ions in the apoplast, cytosol and vacuole of single cells. New sensors for these microelectrodes are being produced which offer lower detection limits and the opportunity to measure other previously unmeasured ions. Measurements can be used to determine the intracellular steady-state activities or report the response of cells to environmental changes.
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Nitz DE, Hogan PB, Schearer LD, Smith SJ. Photodissociation of Na2+in Na2multiphoton absorption. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3700/12/3/007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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111
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Spierto FW, Gardner F, Smith SJ. Evaluation of an EIA method for measuring serum levels of the estrogen metabolite 2-hydroxyestrone in adults. Steroids 2001; 66:59-62. [PMID: 11090660 DOI: 10.1016/s0039-128x(00)00139-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two-hydroxyestrone (2OHE-1) and 16alpha-hydroxyestrone (16OHE-1) are two estrogen metabolites that may play important roles in the development or promotion of breast cancer. Our study assessed the reliability of a newly developed kit procedure for measuring 2OHE-1. Although under certain conditions the assay would not distinguish 2OHE-1 from estriol, or possibly 2-methoxyestrone, steroids such as 17beta-estradiol, estrone and 16OHE-1 should not interfere with the test. Our study evaluated the precision of this enzyme immunoassay (EIA) kit for measuring 2OHE-1 levels in serum obtained from healthy men and women. As a result of several replicate analyses of specimens obtained from 18 men and 20 women, we found that the within-run coefficients of variation (CVs) were approximately 20% and the among run CVs, 30%. Because the SD for the procedure is high, the limit of detection (LOD) was also high (130 ng/l). Nonetheless the assay could distinguish between 2OHE-1 levels in men (128 ng/l) and women (332 ng/l) because we performed a large number of analyses on each specimen. Improving the reproducibility of the assay would reduce the: 1. LOD; number of replicates needed to obtain reliable estimates of 2-OHE-1 levels; amount of time, effort, and cost for each analysis; and greatly improve the reliability of the method. Because the within-run variability is relatively smaller than the total variability (among run + within run), use of the assay for determining differences among groups could be justified only when measurements were made in a single run.
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Abstract
PURPOSE Unilateral seizures, or hemiconvulsive attacks, are motor seizures with tonic and/or clonic phenomena that involve only one side of the body. METHODS We describe three adolescents who presented with hemiconvulsive seizures and were found to have 3-cps generalized spike-and-wave discharges on ictal and/or interictal EEG. All had normal neuroimaging studies. Two patients had been previously treated with carbamazepine, which led to a partial response in one patient. RESULTS All three patients, however, are now seizure free on either sodium valproate or a combination of sodium valproate and lamotrigine. We believe the electroclinical diagnosis is that of idiopathic generalized epilepsy. CONCLUSIONS Idiopathic generalized epilepsy presenting with hemiconvulsive seizures has not, to our knowledge, been previously described. However, the correct diagnosis of an idiopathic generalized seizure disorder, as opposed to a partial seizure disorder, has important treatment implications. The possible mechanism of hemiconvulsive seizures in idiopathic generalized epilepsy is discussed.
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MESH Headings
- Adolescent
- Anticonvulsants/therapeutic use
- Child
- Comorbidity
- Electroencephalography/statistics & numerical data
- Epilepsy, Frontal Lobe/diagnosis
- Epilepsy, Frontal Lobe/drug therapy
- Epilepsy, Frontal Lobe/epidemiology
- Epilepsy, Generalized/diagnosis
- Epilepsy, Generalized/drug therapy
- Epilepsy, Generalized/epidemiology
- Epilepsy, Partial, Motor/diagnosis
- Epilepsy, Partial, Motor/drug therapy
- Epilepsy, Partial, Motor/epidemiology
- Female
- Humans
- Lamotrigine
- Male
- Treatment Outcome
- Triazines/therapeutic use
- Valproic Acid/therapeutic use
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Smith SJ, Kotecha S, Towers N, Mohun TJ. Xenopus Hand2 expression marks anterior vascular progenitors but not the developing heart. Dev Dyn 2000; 219:575-81. [PMID: 11084656 DOI: 10.1002/1097-0177(200012)219:4<575::aid-dvdy1075>3.0.co;2-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have isolated cDNAs encoding the bHLH protein Hand2 in the amphibian Xenopus laevis and analysed Hand2 expression in early development from the onset of gastrulation to feeding tadpole stages. XHand2 is expressed in the branchial arch mesenchyme and also in small bilateral populations of cells in the anterior, ventrolateral region of early tailbud embryos. At later stages, these punctate Hand2-expressing cells are located at the sites of the forming common cardinal veins, suggesting that they may constitute progenitors of vascular smooth muscle cells. Other Hand2-expressing cells are also associated with further components of the forming anterior vasculature but are not detected in mature blood vessels. Interestingly, no myocardial expression of XHand2 can be detected in the developing tadpole heart, in marked contrast to results obtained with chick and mouse embryos.
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Abstract
Climate change mitigation strategies have focused on reductions in carbon dioxide and other long-lived greenhouse gases. Smith et al., investigate the viability of a different strategy, recently proposed by Hansen et al., which focuses on controlling short-lived pollutants such as soot and tropospheric ozone. They conclude that carbon dioxide must remain the primary focus of climate change mitigation strategies.
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Krakow K, Baxendale SA, Maguire EA, Krishnamoorthy ES, Lemieux L, Scott CA, Smith SJ. Fixation-off sensitivity as a model of continuous epileptiform discharges: electroencephalographic, neuropsychological and functional MRI findings. Epilepsy Res 2000; 42:1-6. [PMID: 10996501 DOI: 10.1016/s0920-1211(00)00152-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A case of fixation-off sensitivity (FOS) in an asymptomatic adult is presented and studied as a model for continuous epileptiform discharges. Video-electroencephalographic (EEG) revealed continuous bilateral occipital spike wave discharges during elimination of central vision, which were shown to be associated with transitory cognitive impairment demonstrated by neuropsychological testing. Functional MRI showed activation of parieto-occipital and frontal brain areas during the fixation-off discharges. This localization was confirmed with 64-channel EEG source analysis. The applied methods provided additional information on the pathophysiology of epileptiform discharges.
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Myers GL, Kimberly MM, Waymack PP, Smith SJ, Cooper GR, Sampson EJ. A reference method laboratory network for cholesterol: a model for standardization and improvement of clinical laboratory measurements. Clin Chem 2000; 46:1762-72. [PMID: 11067811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
BACKGROUND Accurate and precise measurement of blood cholesterol plays a central role in the National Cholesterol Education Program's strategy to reduce the morbidity and mortality attributable to coronary heart disease. Matrix effects hamper the ability of manufacturers to adequately calibrate and validate traceability to the National Reference System for Cholesterol (NRS/CHOL). CDC created the Cholesterol Reference Method Laboratory Network (CRMLN) to improve cholesterol measurement by assisting manufacturers of in vitro diagnostic products with validation of the traceability of their assays to the NRS/CHOL. METHODS CRMLN laboratories established the CDC cholesterol reference method (modification of the Abell-Levy-Brodie-Kendall chemical method) and are standardized using CDC frozen serum reference materials. CRMLN laboratories use common quality-control materials and participate in monthly external performance evaluations conducted by CDC. The CRMLN performance criteria require member laboratories to agree with CDC within +/-1.0% and maintain a CV < or =2.0%. RESULTS From 1995 to 200 the CRMLN laboratories met the accuracy criterion 97% of the time and the precision criterion 99% of the time. During this time period, the CRMLN maintained an average bias to CDC of 0.01% and an average collective CV of 0.33%. CONCLUSIONS CDC established the CRMLN as the first international reference method laboratory network. The CRMLN assists manufacturers in the validation of the calibration of their diagnostic products so that clinical laboratories can measure blood cholesterol more reliably. The CRMLN can serve as a model for other clinical analytes where traceability to a hierarchy of methods is needed and matrix effects of the field methods with processed calibrators or reference materials are present.
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Waters J, Smith SJ. Phorbol esters potentiate evoked and spontaneous release by different presynaptic mechanisms. J Neurosci 2000; 20:7863-70. [PMID: 11050105 PMCID: PMC6772716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Phorbol esters enhance release from a variety of cell types. The mechanism by which phorbol esters potentiate presynaptic release from central neurons is unclear, although effects of phorbol esters both on the readily releasable pool of vesicles and on presynaptic calcium channels have been shown. Using confocal microscopy and the fluorescent styryl dye FM 1-43, we have examined the effects of phorbol-12,13-dibutyrate (PDBu) on presynaptic vesicle turnover at individually identified synapses in dissociated cultures obtained from neonatal rat hippocampus. Using different dye staining and destaining protocols we were able to resolve two effects of PDBu. Potentiation of evoked release by PDBu was insensitive to calcium channel antagonists, suggesting that this effect results from an increased number of vesicles in the readily releasable pool. Since we observed no effect of PDBu on the size of the total recycling vesicle pool, we conclude that phorbol esters alter the equilibrium between reserve and readily releasable pools. An additional effect of PDBu on spontaneous release was observed. This effect was antagonized by nifedipine but not omega-conotoxin GVIA or omega-agatoxin IVA. We conclude that PDBu influences spontaneous and evoked release by two different mechanisms: through L-type calcium channels and through an increase in the proportion of recycling vesicles in the readily releasable pool. In addition to further clarifying the mechanism of action of phorbol esters, these results suggest that phorbol esters may be a useful tool with which to probe the function of the readily releasable pool of presynaptic vesicles at CNS synapses.
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Thompson SA, Duncan JS, Smith SJ. Partial seizures presenting as panic attacks. BMJ (CLINICAL RESEARCH ED.) 2000; 321:1002-3. [PMID: 11039971 PMCID: PMC1118775 DOI: 10.1136/bmj.321.7267.1002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Lapouge K, Smith SJ, Walker PA, Gamblin SJ, Smerdon SJ, Rittinger K. Structure of the TPR domain of p67phox in complex with Rac.GTP. Mol Cell 2000; 6:899-907. [PMID: 11090627 DOI: 10.1016/s1097-2765(05)00091-2] [Citation(s) in RCA: 236] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
p67phox is an essential part of the NADPH oxidase, a multiprotein enzyme complex that produces superoxide ions in response to microbial infection. Binding of the small GTPase Rac to p67phox is a key step in the assembly of the active enzyme complex. The structure of Rac.GTP bound to the N-terminal TPR (tetratricopeptide repeat) domain of p67phox reveals a novel mode of Rho family/effector interaction and explains the basis of GTPase specificity. Complex formation is largely mediated by an insertion between two TPR motifs, suggesting an unsuspected versatility of TPR domains in target recognition and in their more general role as scaffolds for the assembly of multiprotein complexes.
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Abstract
The recent discovery of HFE, the MHC-Class-I-like gene mutated in up to 90% of patients with hereditary haemochromatosis, and the gene encoding the Nramp2/divalent metal transporter-1 (DMT-1) implicated in ferrous iron transport holds promise for a greater understanding of human iron metabolism. Since the HFE protein can be crystallized as a ternary complex with the transferrin receptor and iron-saturated transferrin, and DMT-1 expression is up-regulated in hereditary haemochromatosis, these proteins are likely to interact in a common pathway for human iron homeostasis. To investigate the cellular interactions between the cognate proteins encoded by these genes, we generated a panel of rabbit and avian antisera from human HFE and DMT-1 derived peptides. The antibodies were characterized by ELISA reactions and Western immunoblotting. Immunohistochemical staining showed that DMT-1 protein localized to the brush border of human duodenum where it is predicted to serve as the principal transporter of ferrous iron from the intestinal lumen. In the human cell lines, Caco-2 (small intestinal phenotype upon differentiation) and K562 (erythroleukaemic) HFE, in the presence of iron-saturated transferrin, co-localized with transferrin receptors in an early endosome compartment using confocal immunofluorescence microscopy. This interaction may be critical in small-intestinal crypt cells which express HFE, where it may function to modulate their intrinsic iron status thereby programming iron absorption by DMT-1 in the mature enterocyte. In undifferentiated Caco-2 cells, DMT-1 localized to a discrete late endosome compartment distinct from that occupied by HFE where, in addition to brush-border iron uptake, it may function to regulate the availability of iron delivery to intracellular iron pools. Disruption of the HFE gene as a result of mutations associated with hereditary haemochromatosis may thus impair homeostatic mechanisms controlling iron absorption within the small-intestine epithelium by a direct interaction with transferrin receptors and by subsequent alteration of DMT-1 expression. Identification of the molecular interactions of HFE with DMT-1 and other key components of the iron transport pathway has implications for a mechanistic understanding of the pathophysiology of human iron storage diseases as well as the regulation of normal iron balance.
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Everitt AD, Thomas DJ, Smith SJ. Late onset cryptogenic photomyoclonus: case report. Eur Neurol 2000; 41:168-9. [PMID: 10202250 DOI: 10.1159/000008043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Shakib F, Hooi DS, Smith SJ, Furmonaviciene R, Sewell HF. Identification of peptide motifs recognized by a human IgG autoanti-IgE antibody using a phage display library. Clin Exp Allergy 2000; 30:1041-6. [PMID: 10848928 DOI: 10.1046/j.1365-2222.2000.00852.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The potential of murine monoclonal anti-IgE antibodies as long-term therapy for atopic diseases will have to rely, for the time being, on passive antibody administration. There is therefore considerable interest in developing a peptide-based vaccine for active immunization to elicit long-term protective anti-IgE antibodies in the patient. It has been shown that some human IgG autoanti-IgE antibodies have the ability to partially block the binding of IgE to Fc receptors such as Fc epsilonRI. Therefore, the epitopes recognized by such antibodies could have vaccine potential. OBJECTIVE To determine the epitope specificity of one such human IgG anti-IgE antibody. METHODS A 15-mer phage-peptide library was used to establish the epitope specificity of an IgG anti-IgE antibody isolated from the serum of an asthma patient. RESULTS The SRPSP sequence, or part of it (i.e. RPS, RPSP, SPS or PSP), was present in all 18 phage-peptides that have been sequenced. This common motif was found to be within the human epsilon chain sequence Ser341-Thr355 near the N-terminus of the C epsilon3 domain. According to the human Fc epsilon model, the most accessible residues in this sequence are Arg342, Ile350, Arg351, Lys352 and Ser353. CONCLUSIONS The present data should provide the molecular basis for the rational design of a suitable peptide immunogen (vaccine) for boosting the production of protective autoanti-IgE antibodies.
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Smith SJ. Uterine fibroid embolization. Am Fam Physician 2000; 61:3601-7, 3611-2. [PMID: 10892632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Interventional radiologists have performed uterine artery embolization to treat women with emergency uterine bleeding since the 1970s. In this procedure, the physician guides a small angiographic catheter into the uterine arteries and injects a stream of tiny particles that decreases blood flow to the uterus. It is now considered a safe and highly effective nonsurgical treatment of women with symptomatic uterine fibroid tumors. Uterine fibroid embolization has several advantages over conventional hormonal suppression and surgical procedures, including avoidance of the side effects of drug therapy and the physical and psychologic trauma of surgery. In addition, after uterine fibroid embolization, patients can normally resume their usual activities several weeks earlier than they can after hysterectomy. Along with hysteroscopic resection, myolysis and laparoscopic myomectomy, uterine fibroid embolization widens treatment options for patients who desire to avoid hysterectomy.
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Chrisman HB, Saker MB, Ryu RK, Nemcek AA, Gerbie MV, Milad MP, Smith SJ, Sewall LE, Omary RA, Vogelzang RL. The impact of uterine fibroid embolization on resumption of menses and ovarian function. J Vasc Interv Radiol 2000; 11:699-703. [PMID: 10877413 DOI: 10.1016/s1051-0443(07)61627-3] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To evaluate the effect of uterine fibroid embolization (UFE) on menstruation and ovarian function. METHODS The authors performed an observational study of UFE for the treatment of symptomatic fibroids. All patients had regular predictable menses before intervention and none had clinical or laboratory findings of menopause. UFE was performed with use of standard methods with 355-700-microm-diameter polyvinyl alcohol (PVA) foam particles. The incidence of ovarian failure was calculated for women younger than 45 years and for those 45 years or older, based on retrospective stratification by age. The authors assessed statistical differences in ovarian failure between the two age groups with use of the X2 test. RESULTS Sixty-six premenopausal women (age range, 30-55 years) underwent bilateral UFE and were followed for an average of 21 weeks (range, 12-77 weeks). In 56 of 66 (85%) patients, regular menses resumed after an average of 3.5 (range, 1-8) weeks. In 10 of 66 (15%) patients, regular menses did not resume. Clinical and biochemical findings consistent with ovarian failure and presumed menopause were seen in nine of 10 patients without resumption of menses (14% of total patients). Ovarian failure occurred in nine of 21 (43%) women older than 45 years and in none of the 45 women younger than 45 years (P < .05). There were no differences in presenting symptoms, amount of PVA used, or fibroid size between patients who did and did not resume menses. CONCLUSION The majority of patients undergoing UFE will have resumption of menses, but the incidence of postprocedure ovarian failure is considerably higher than reported to date. Loss of menses induced by UFE is significantly more likely to occur in women older than 45 years.
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