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Bartlett DW, Jadeja SP, Austin RS, Charalambous P, Stewart B, Ruan Q, Won B, Dogu N, Vandeven M, Lavender S. Pilot clinical study to evaluate the efficacy of a professionally delivered high fluoride varnish on erosive tooth wear in an in-situ model. J Dent 2024; 143:104884. [PMID: 38373521 DOI: 10.1016/j.jdent.2024.104884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024] Open
Abstract
OBJECTIVES The aim for this pilot study was to investigate the effect of a sodium fluoride varnish on step height measured by a profilometer from human enamel worn by healthy volunteers with a novel in situ/ex vivo erosion design. METHOD Healthy volunteers aged 18-70 years wore a palatal splint containing 8 human enamel samples and underwent two 3-day treatment periods for 6 h a day with a varnish containing sodium fluoride at 22,600 ppm and the control with the same ingredients but without fluoride. Each splint contained 4 polished and 4 unpolished samples. The interventions were applied to the surface of the enamel samples in randomised order, removed after 6 h, then immersed ex-vivo in 1 %, pH 2.7 citric acid for 2 min, repeated 4 times a day, over 2 days. Measurements of enamel were assessed blindly by microhardness on day 2 and by non-contact laser profilometry on day 3 for the two treatments. RESULTS 24 volunteers, 2 males and 22 females aged 27-54 years, were screened and recruited. The delta microhardness, from polished samples removed at the end of day 2, for the control and fluoride treatment was 95.7 (22.9) kgf/mm2 and 123.7 (28.9) kgf/mm2, respectively (p < .005). The mean (SD) step height for the control polished enamel surfaces was 3.67 (2.07) µm and for the fluoride varnish was 1.79 (1.01) µm (p < .0005). The control unpolished enamel surfaces had a mean 2.09 (1.53) µm and the fluoride varnish was 2.11 (1.53) µm but no statistical difference was detected. CONCLUSIONS The results from this pilot study, utilizing an in-situ model where enamel was exposed to acid over the course of 2 days, demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm prevented erosive wear compared to a control on the polished enamel surfaces. CLINICAL SIGNIFICANCE Intra-oral study demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm reduced erosive tooth wear.
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Affiliation(s)
- David W Bartlett
- Centre for Clinical, Oral and Translational Sciences, Faculty of Dentistry, Oral and Clinical Sciences, King's College London, London, SE1 9RT, United Kingdom.
| | - Sagar P Jadeja
- Centre for Clinical, Oral and Translational Sciences, Faculty of Dentistry, Oral and Clinical Sciences, King's College London, London, SE1 9RT, United Kingdom
| | - Rupert S Austin
- Centre for Clinical, Oral and Translational Sciences, Faculty of Dentistry, Oral and Clinical Sciences, King's College London, London, SE1 9RT, United Kingdom
| | - Polyvios Charalambous
- Centre for Clinical, Oral and Translational Sciences, Faculty of Dentistry, Oral and Clinical Sciences, King's College London, London, SE1 9RT, United Kingdom; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, the University of Manchester, Manchester, M15 6FH, United Kingdom
| | - Bernal Stewart
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
| | - Qichao Ruan
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
| | - Betty Won
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
| | - Nihal Dogu
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
| | - Mark Vandeven
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
| | - Stacey Lavender
- Colgate Palmolive Company, Global Technology Center, Piscataway, NJ, USA
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Abu Baker D, Patel S, Charalambous P, Albuloushi N, Rodriguez J. Multi-Modal Digital Impressions For Palatal Defects. Eur J Prosthodont Restor Dent 2024; 32:75-82. [PMID: 37721541 DOI: 10.1922/ejprd_2586abubaker08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023]
Abstract
INTRODUCTION This in-vitro study investigated limitations of intra-oral scanners (IOS) in capturing palatal defects at decreased mouth openings. The trueness and precision of composite 3D-printed models from Cone-Beam Computed Tomography (CBCT) and IOS were measured. METHODS A partially dentate palatal defect model was scanned with IOS (3M™TrueDefinition) at various simulated mouth openings. Five silicone impressions were poured in gypsum. Scans were taken using 3M™TrueDefinition; Planmeca Planscan®, n=5 each. Model was scanned on two CBCT (PlanmecaProFace®; Accuitomo170®CBCT, n=5 each). Geomagic®Control2014™ was used to create composite-models merging CBCT with IOS. Thirty composite-models were 3D-printed. Trueness and precision were measured. Pearson Correlation Coefficients measured correlation between mouth opening and data capture. Data analysed using Kruskal-Wallis, Wilcoxon rank-sum, and ANOVA. Statistical significance inferred when p⟨0.05. RESULTS Mouth openings ⟨20mm, IOS didn't capture information of soft tissue. Increased mouth opening positively correlated with increased data capture(r=0.93, p=0.001). AccuitomoCBCT and TrueDefinition IOS composite-models had the highest (trueness) and [precision](median (IQR) 0.172 mm(0.062-0.426)); [mean [SD] 0.080 mm [0.008]]. Casts had the lowest results (median (IQR) 0.289 mm(0.119-1.565));[mean [SD] 0.338 mm [0.089]](p⟨0.001). CONCLUSION Mouth opening ⟨20mm resulted in insufficient data capture by IOS for clinical applications. Composite digital models showed promising trueness and precision results.
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Affiliation(s)
- D Abu Baker
- Assistant Professor, Department of Prosthodontics, University of Jordan, Amman, Jordan
| | - S Patel
- Specialist Registrar in Restorative Dentistry, Guy's and St Thomas's Trust, NHS, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT
| | - P Charalambous
- Clinical Lecturer, Bristol University, Bristol Dental School, Bristol
| | - N Albuloushi
- Registrar, King's College London, Guy's Campus, London, UK
| | - J Rodriguez
- Consultant in Restorative Dentistry, Honorary Senior Clinical Lecturer, Guy's and St Thomas's Trust, NHS, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT
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Charalambous P, O'Toole S, Austin R, Bartlett D. The threshold of an intra oral scanner to measure lesion depth on natural unpolished teeth. Dent Mater 2022; 38:1354-1361. [PMID: 35750507 PMCID: PMC10112273 DOI: 10.1016/j.dental.2022.06.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/28/2022] [Accepted: 06/05/2022] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To investigate the threshold and accuracy of intraoral scanning in measuring freeform human enamel surfaces. METHODS Software softgauges, ranging between 20 and 160 µm depth, were used to compare four workflow analysis techniques to measure step height on a freeform surface; with or without reference areas and in combination with surface-subtraction to establish which combination produced the most accurate outcome. Having established the optimum combination, 1.5 mm diameter, individual depths ranging from 11 to 81 µm were created separately on 14 unpolished human enamel samples and then scanned with gold standard laboratory optical profilometry (NCLP, TaiCaan Technologies™, XYRIS2000CL, UK) and a clinical intraoral scanner (TrueDefinition™, Midmark Corp., USA). The sequence of surface registration and subtraction determined from the softgauges was used to measure step height on natural human enamel surfaces. Step heights (μm) were compared using two-way ANOVA with post-hoc Bonferroni (p < 0.05) and Bland-Altman analyses. RESULTS Software differences were significantly reduced from - 29.7 to - 32.5% without, to - 2.4 to - 3.6% with reference areas (p < 0.0001) and the addition of surface-subtraction after registration reduced this further to 0.0 to - 0.3% (p < 0.0001). The intraoral scanner had a depth discrimination threshold of 73 µm on unpolished natural enamel and significant differences (p < 0.05) were observed compared to NCLP below this level. SIGNIFICANCE The workflow of combining surface-registration and subtraction of surface profiles taken from intraoral scans of freeform unpolished enamel enabled confident measurement of step height above 73 µm. The limits of the scanner is related to data capture and these results provide opportunities for clinical measurement.
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Affiliation(s)
- Polyvios Charalambous
- King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, Tower wing, London SE1 9RT, UK.
| | - Saoirse O'Toole
- King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, Tower wing, London SE1 9RT, UK.
| | - Rupert Austin
- King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, Tower wing, London SE1 9RT, UK.
| | - David Bartlett
- Centre for Oral, Clinical & Translational Sciences, King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, Tower wing, London SE1 9RT, UK.
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O'Toole S, Charalambous P, Almatrafi A, Mukar S, Elsharkawy S, Bartlett D. Progress and limitations of current surface registration methods when measuring natural enamel wear. J Dent 2021; 112:103738. [PMID: 34182060 DOI: 10.1016/j.jdent.2021.103738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/17/2021] [Accepted: 06/19/2021] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVES Our ability to detect dental wear on sequential scans is improving. This experiment aimed to determine if widely used surface registration methods were sufficiently accurate to distinguish differences between intervention groups on early wear lesions. METHODS Baseline measurements were taken on human molar buccal enamel samples (n = 96) with a confocal scanning profilometer (Taicaan, UK). Samples were randomly assigned to subgroups of brushing (30 linear strokes 300 g force) before or after an acid challenge (10 min citric acid 0.3% immersion) for four test dentifrices (medium abrasivity NaF, medium abrasivity SnF2, low abrasivity NaF and a water control). Post-experimental profilometry was repeated. 3D step height was analysed using WearCompare (www.leedsdigitaldentistry.co.uk/wearcompare, UK). Percentage Sa change was calculated using Boddies (Taicaan Technologies, Southampton, UK). Data were analysed in SPSS (IBM, USA). RESULTS The mean 3D step height (SD) observed when samples were brushed before the erosive challenge was -2.33 µm (3.46) and after was -3.5 µm (5.6). No significant differences were observed between timing of toothbrushing or dentifrice used. The mean % Sa change for the low abrasivity group (water control and low abrasivity NaF) was -10.7% (16.8%) and +28.0% (42.0%) for the medium abrasivity group (medium abrasivity NaF and SnF2). CONCLUSIONS Detectable wear scars were observed at early stages of wear progression. However standard deviations were high and the experiment was underpowered to detect significant changes. Brushing with a low abrasivity dentifrice or water control produced a smoother surface whereas brushing with a high abrasivity dentifrice produced a rougher surface. CLINICAL SIGNIFICANCE The methodology currently used to align sequential scans of teeth and measure change is too imprecise to measure early wear on natural enamel surfaces unless a large sample size is used. Further improvements are required before we can fully assess early wear processes on natural teeth using profilometry.
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Affiliation(s)
- Saoirse O'Toole
- Centre for Clinical, Oral and Translational Sciences, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK; Department of Prosthodontics, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK.
| | - Polyvios Charalambous
- Centre for Clinical, Oral and Translational Sciences, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK
| | - Ali Almatrafi
- Department of Prosthodontics, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK
| | - Sandeep Mukar
- Department of Prosthodontics, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK
| | - Sherif Elsharkawy
- Centre for Clinical, Oral and Translational Sciences, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK; Department of Prosthodontics, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK
| | - David Bartlett
- Centre for Clinical, Oral and Translational Sciences, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK; Department of Prosthodontics, Faculty for Dental, Oral and Craniofacial Sciences, King's College London, Guy's Hospital, SE1 9RT, UK
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Fattah Z, Chita S, Charalambous P, Colaço CB. AB0795 Hospital anxiety and depression scale (hads) is a ‘non-discriminatory’ patient related outcome measure (prom) in a rheumatology long term condition (ltc) clinic. Ann Rheum Dis 2013. [DOI: 10.1136/annrheumdis-2013-eular.3117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Colaço CB, Fattah Z, Charalambous P. AB0645 Sarcoid / granulomatous disease in association with helicobacter pylori. Ann Rheum Dis 2013. [DOI: 10.1136/annrheumdis-2013-eular.2967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Grivas TB, Patias P, Soultanis K, Stylianidis E, Tsioukas V, Georgiadis C, Andreou C, Charalambous P, Chrysanthou Y. Design, implementation and first results of a 3RD generation digital photogrammetric system from trunk surface assessment and scoliosis screening. Scoliosis 2012. [PMCID: PMC3304850 DOI: 10.1186/1748-7161-7-s1-p14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- TB Grivas
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - P Patias
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - K Soultanis
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - E Stylianidis
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - V Tsioukas
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - C Georgiadis
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - C Andreou
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - P Charalambous
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
| | - Y Chrysanthou
- “Tzanio” General Hospital of Piraeus, Pirae Brilissia, Greece
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Chita S, Anie K, Charalambous P, Colaço CB. P82 Audit of patient-reported outcome measures (proms) in chronic musculoskeletal disease clinics. Indian Journal of Rheumatology 2011. [DOI: 10.1016/s0973-3698(11)60192-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Gatzioufas Z, Charalambous P, Loew U, Kozobolis V, Schirra F, Krause M, Seitz B. Evidence of oxidative stress in Schnyder corneal dystrophy. Br J Ophthalmol 2010; 94:1262-4. [PMID: 20530186 DOI: 10.1136/bjo.2009.160366] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Gatzioufas Z, Charalambous P, Seitz B, Evers S, Jonescu-Cuypers C, Krause M, Thanos S. Cholinergic inhibition by botulinum toxin in a rat model of congenital glaucoma raises intraocular pressure. Br J Ophthalmol 2008; 92:826-31. [PMID: 18356261 DOI: 10.1136/bjo.2007.128033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Cholinergic receptors are crucially involved in the regulation of intraocular pressure (IOP). Muscarinic agonists in the trabecular meshwork tissue increase aqueous humour outflow facility by a direct stimulation of ciliary muscle contraction. We investigated the contribution of cholinergic state to IOP regulation. METHODS Intracameral injections of botulinum toxin A (BTA) were applied in a group with four normotensive rats and a group with four glaucoma rats (genetic glaucoma model). BTA is a potent neurotoxin which inhibits presynaptic cholinergic transmission for 6-8 weeks. The same amount of saline was injected in a third group of four normotensive rats (sham condition). IOP measurements were performed preoperatively, as well as 1, 2 and 4 weeks postoperatively. Afterwards, the rat eyes were removed and subjected to immunhistochemistry and western blotting analysis using antibodies against choline acetyltransferase (CHAT). RESULTS Mean IOP in both normotensive groups was unaltered compared with the preoperative status. The glaucoma group showed a significant increase in the mean IOP (Student test, p<0.05) and a signal reduction for CHAT by immunolabelling in the trabecular meshwork compared with the other two groups. Western blotting confirmed the decreased expression of CHAT. CONCLUSION Our results suggest that modification of the cholinergic status in the normotensive eye does not significantly affect the IOP; cholinergic regulation of the ciliary trabecular meshwork may have differential levels of control, apart from the ciliary muscle contraction. Moreover, it seems that differential expression of the muscarinic receptors may be responsible for the decreased trabecular cholinergic state occurring in this rat model of glaucoma.
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Affiliation(s)
- Z Gatzioufas
- Department of Experimental Ophthalmology, School of Medicine, University Eye Hospital Muenster, Muenster, Germany.
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Abstract
PURPOSE The purpose of the present study was to examine whether keratoconus, which is a bilateral noninflammatory corneal ectasia with multifactorial aetiology, shows altered expression of Connexin (Cx43). Cx43 is an important gap junction protein that contributes crucially to epithelial and stromal integrity of cornea. METHODS Eight keratoconic human corneal buttons were examined with immunohistochemistry and Western blotting and compared with eight normal human corneal buttons, to unravel changes in Cx43 expression. RESULTS All normal corneas exhibited similar epithelial Cx43 expression patterns, with the protein located in the basal epithelial layer. In contrast, some keratoconic corneas showed an altered pattern of immunostaining and Western blotting confirmed a decreased expression of Cx43 in keratoconic corneas. CONCLUSIONS Our results indicate that a decrease in Cx43 amount together with functional alteration of the protein is associated with keratoconus pathophysiology However, these changes apply only to some of the corneas examined and may not generally account for the development of keratoconus.
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Affiliation(s)
- Z Gatzioufas
- Department of Experimental Ophthalmology, University Eye Hospital Muenster, Muenster, Germany
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Kaulich B, Susini J, David C, Di Fabrizio E, Morrison GR, Thieme J, Wilhein T, Kovac J, Bacescu D, Salome M, Dhez O, Weitkamp T, Cabrini S, Gosperini A, Charalambous P, Vogt U, Podnar M, Kiskinova M. TwinMic: Combined scanning and full‐field imaging microscopy with novel contrast mechanisms. ACTA ACUST UNITED AC 2003. [DOI: 10.1080/08940880308603022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kaulich B, Bacescu D, Cocco D, Susini J, Salomé M, Dhez O, David C, Weitkamp T, Di Fabrizio E, Cabrini S, Morrison G, Charalambous P, Thieme J, Wilhein T, Kovac J, Podnar M, Kiskinova M. Twinmic: A European twin microscope station combining full-field imaging and scanning microscopy. ACTA ACUST UNITED AC 2003. [DOI: 10.1051/jp4:200300039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
A brief description is given of a scanning transmission X-ray microscope (STXM) for use with synchrotron radiation allowing simultaneous X-ray imaging and imaging of surface topography. Surface topography, appropriate to both conducting and non-conducting samples, is sensed by successive "specimen hopping" i.e. planting of the specimen at and withdrawal from a fixed sharp tip, or stylus, formed by the scanning tip of an atomic force microscope (AFM). First experiments are described with 3 keV photons with zone plate resolution of about 100 nm. Preliminary work is also mentioned to add a collimator to improve spatial resolution (in principle to < 20 nm for 300-500 eV photons), by installing a pierced AFM tip at the zone plate focus. The topographic measurement, currently with specimen thickness resolution of about 10 nm, but potential for approximately 1 nm, and feature-dependent in-specimen plane resolution of about 100 nm as limited by the stylus geometry, is an adjunct to the STXM results, to provide information helpful in the interpretation of the X-ray image. Examples are given for simple specimens of the gains in specimen understanding from simultaneous STXM and hopping contact topographic images. Typical applications areas are radiation damage, and dynamic processes like specimen corrosion.
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Affiliation(s)
- M T Browne
- Physics Department, King's College, Strand, London, UK
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Deugnier YM, Charalambous P, Le Quilleuc D, Turlin B, Searle J, Brissot P, Powell LW, Halliday JW. Preneoplastic significance of hepatic iron-free foci in genetic hemochromatosis: a study of 185 patients. Hepatology 1993; 18:1363-9. [PMID: 7902316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Sublobular nodules of hepatocytes free of iron or exhibiting much less iron than the surrounding parenchyma, referred to in this study as iron-free-foci, are frequently found in the livers of patients with genetic hemochromatosis complicated by hepatocellular carcinoma. To test the hypothesis that such nodules are preneoplastic lesions, iron-free foci were sought in the initial liver biopsy specimens of 185 patients with untreated and uncomplicated genetic hemochromatosis. Iron-free foci were found in 14 (7.6%) patients, all men, aged from 38 to 76 yr, with heavy iron overload and with fibrosis or cirrhosis. Twelve patients with iron-free foci were followed for 0.9 to 15 yr (7 +/- 6 yr). In six (50%), HCC developed, compared with 2 (8%) from a control group consisting of 24 patients without IFF matched according to age, sex, degree of fibrosis, liver iron amount and follow-up duration. The mean number of iron-free foci per iron-free foci-positive specimen was 3.2 +/- 2.1. Ten patients had dysplastic aspects in their iron-free foci, and four had intrahepatocytic iron-positive inclusions at the periphery of iron-free foci. Proliferative cell nuclear antigen was positive in 75% of iron-free foci and in 24% +/- 21% of hepatocyte nuclei in iron-free foci. This study clearly demonstrates that iron-free foci are proliferative lesions and strongly suggests that such nodules are preneoplastic foci. Therefore the finding of IFF in the initial liver biopsy specimen from a patient with genetic hemochromatosis should lead to regular screening for hepatocellular carcinoma.
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Affiliation(s)
- Y M Deugnier
- Clinique des Maladies du Foie, Centre Hospitalier Régional et Universitaire, Rennes, France
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Roberts FD, Charalambous P, Fletcher L, Powell LW, Halliday JW. Effect of chronic iron overload on procollagen gene expression. Hepatology 1993; 18:590-5. [PMID: 8359800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The pathogenesis of hepatic fibrosis and cirrhosis in genetic hemochromatosis may involve a direct effect of excess iron on collagen synthesis in the liver. To investigate this theory, we measured procollagen messenger RNA levels (types I, III and IV) in the livers of rats in which we produced chronic parenchymal iron overload by feeding them dietary carbonyl iron (2.5%, wt/wt) for up to 18 mo. This feeding resulted in predominantly parenchymal iron deposition in a periportal distribution similar to that seen in genetic hemochromatosis. Increased amounts of collagen fibrils were observed in iron-loaded livers on electron microscopy; all iron-loaded livers showed some periportal fibrosis. Although very high hepatic iron concentrations (range = 340 to 1,100 mumol/gm dry wt) were achieved in the carbonyl iron-loaded rats, we saw no consistent difference between steady-state messenger RNA levels for procollagens types I, III and IV in control and iron-loaded livers examined at five different time points up to 18 mo. Messenger RNA levels of the cytokine transforming growth factor-beta 1, which has been implicated as having a role in the production of extracellular matrix proteins, were also measured. No significant differences were observed between iron-loaded and control livers. These results suggest that excess parenchymal iron does not have a direct effect on the expression of the procollagens or transforming growth factor-beta 1 genes in iron-loaded livers and that factors other than, or in addition to, iron are necessary for fibrosis to occur.
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Affiliation(s)
- F D Roberts
- Liver Unit, Queensland Institute of Medical Research, Brisbane, Australia
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Burge RE, Browne MT, Charalambous P, Slark GE, Smith PJ, Lewis CL, Neely D. Suboptical x-ray imaging using the Vulcan x-ray laser. Opt Lett 1993; 18:661. [PMID: 19802233 DOI: 10.1364/ol.18.000661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Abstract
The effects of pyrethroids and DDT on the alpha-subunit protein of the rat brain sodium channel were studied by using both native and exogenously added cAMP-dependent protein kinases. For this purpose, the sodium channel was partially purified, using the method of Hartshorne and Catterall [J Biol Chem 259: 1667-1675, 1984], and 32P-phosphorylated using [gamma-32P]ATP and exogenously added catalytic subunit of cAMP-dependent protein kinase. By comparing the phosphorylation patterns of the isolated sodium channel to those of the partially purified or unpurified (i.e. intact synaptosomes) preparations, it was concluded that the alpha-subunit of the voltage-sensitive sodium channel protein is the only phosphorylatable protein present at the 260 kD molecular weight range on the sodium dodecyl sulfate-polyacrylamide gel electrophoretogram. Phosphorylation of the alpha-subunit was induced by depolarization, and this process was inhibited by 10(-6) to 10(-10) M 1R-deltamethrin, but not by 1S-deltamethrin, the latter being an inactive enantiomer of the former. DDT produced a similar effect, but only at a higher concentration range. By using lysed synaptosomal membranes, it was possible to study the direct effects of these compounds on the alpha-subunit, which were similar to those produced by depolarization of intact synaptosomes.
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Affiliation(s)
- Y Ishikawa
- Pesticide Research Center, Michigan State University, East Lansing 48824
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Abstract
A brief description is given of the eight image signals that can be simultaneously recorded in digital form using an appropriate data recording system and high resolution STEM; this involves a set of detectors covering bright and dark field. Details are provided of the collection and manipulation of image data for STEM, including on-line estimation of off-focus distance, on-line assessment of astigmatism, on-line signal to noise ratio in any or all detectors; examples of all three procedures are given. The use of the data recording system is discussed together with some aspects of image display, including the use of colour. A method is introduced of providing, using the appropriate hardware, a prescribed colour map (image intensity converted to colour) using replaceable PROMS. Two off-line procedures are considered. One is the Karhunen-Loeve transform and its application to bringing together the information contained within the multiple signals, and the other is the discrete cosine transform by which the storage problem for digital image storage may be reduced, according to the image, by between 15 and 30 times.
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