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Mohammadi S, Asghari E, Attarchi MS. Evaluation of skin diseases and disorders in photographers. Indian J Occup Environ Med 2009; 13:88-91. [PMID: 20386626 PMCID: PMC2847333 DOI: 10.4103/0019-5278.55126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Occupational skin disease is very common and important among photographers due to the chemical substances used in photographic processes. In this cross-sectional study, 100 photographers were asked about their occupational exposures in their workplace. Physical examinations were done to find skin diseases and information about demographic factors and history of other skin diseases was collected via a questionnaire. This study examined 100 people, 86 men and 14 women; 37% of these 100 subjects were found to suffer from skin diseases and disorders: 24% contact dermatitis, 2% leukoderma, 3% nail hyperpigmentation. Less than half of these subjects (43%) were found to be working with nonmechanized (manual) printers whereas the other 57% worked with computerized printers. Employees working with nonmechanized printers were found to have a statistically meaningful increase in skin diseases compared with subjects who were working with computerized printers (Odds ratio = 7.4, 95% CI = 2.59−21.92, P = 0.001). Some (41%) of these subjects did not use gloves and were found to have a statistically significant increased incidence of skin diseases compared with the ones who used gloves (Odds ratio = 4.11, 95% CI = 1.72–13.21, P value = 0.002). Generally, it seems that adequate ventilation and protective gloves are necessary for decreasing the prevalence of occupational skin diseases among photographers. Also, educating the photographers about the risks of the chemical substances in their workplace is very important.
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102
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Deppe M, Kellinghaus C, Duning T, Möddel G, Mohammadi S, Deppe K, Schiffbauer H, Kugel H, Keller SS, Ringelstein EB, Knecht S. Nerve fiber impairment of anterior thalamocortical circuitry in juvenile myoclonic epilepsy. Neurology 2008; 71:1981-5. [PMID: 19064879 DOI: 10.1212/01.wnl.0000336969.98241.17] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- M Deppe
- Department of Neurology, University of Muenster, Albert-Schweitzer-Str. 33, 48129 Muenster, Germany.
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Abstract
Background Lead poisoning is a common occupational health hazard in developing countries and many misdiagnoses and malpractices may occur due to unawareness of lead poisoning symptoms. Case presentation We report a case of occupational lead poisoning in an adult battery worker with abdominal colic who initially underwent appendectomy with removal of normal appendix. Later on he was diagnosed with lead poisoning and was treated appropriately with lead chelator (CaNa2EDTA). Conclusion Lead poisoning is frequently overlooked as the differential diagnosis of acute abdomen which may result in unnecessary surgery. Appropriate occupational history taking is helpful in making a correct diagnosis. Occupational lead poisoning is a preventable disorder and a serious challenge for the health and labor authorities in developing countries.
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Affiliation(s)
- S Mohammadi
- Department of Occupational Medicine and Occupational Medicine Research Center of Iran University of Medical Sciences, Shaheed Hemmat highway, Tehran, Iran.
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104
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Day E, Betler J, Mohammadi S, Reitz B, Parda D, Miften M. TH-C-351-05: Quantitative Methods for Contouring On PET-CT Images. Med Phys 2008. [DOI: 10.1118/1.2962861] [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: 11/07/2022] Open
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105
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Aazami MA, Mohammadi S. Determination of the best temperature and dry condition in carrot primed-seeds. Pak J Biol Sci 2008; 11:1502-5. [PMID: 18817255 DOI: 10.3923/pjbs.2008.1502.1505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Seed priming and drying condition effects were investigated immediately after seed-priming and 9 week after the storage. In this experiment, carrot seeds of 'Forto C.V.' were used. These seeds were individually primed for 10 days at 20 degrees C and in PEG (6000) (273 g L(-1)) and KNO3 (200 mmol) solutions. Then they were dried for 1 and 2 h at 15, 25 and 30 degrees C, respectively. One part of the seeds was stored at 5 degrees C in RH/45% For 9 week. Chemical priming effects, drying temperature as well as germination temperature on different traits especially germination percentage were significant. However, drying time had no significant effect on germination percentage after storage period. PEG priming and drying at 25 degrees C for 2 h provided the best condition for germination percentage. Using the best material for pre-priming, along with suitable drying management with appropriate quality and good conditions of the storage is important.
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Affiliation(s)
- M A Aazami
- Department of Horticulture, Maragheh Higher Education Complex, University of Tabriz, Tabriz-5166616471, Iran
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106
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Kleffner I, Deppe M, Mohammadi S, Schiffbauer H, Stupp N, Lohmann H, Young P, Ringelstein EB. DIFFUSION TENSOR IMAGING DEMONSTRATES FIBER IMPAIRMENT IN SUSAC SYNDROME. Neurology 2007; 70:1867-9. [DOI: 10.1212/01.wnl.0000280580.95671.01] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Mohammadi S, Bonnet N, Leprince P, Charbonneau E, Berberian G, Aslani M, Silvaggio G, Dorent R, Pavie A, Gandjbakhch I. Long-term Survival of Heart Transplant Recipients with Lung Cancer: The Role of Chest Computed Tomography Screening. Thorac Cardiovasc Surg 2007; 55:438-41. [PMID: 17902066 DOI: 10.1055/s-2007-965306] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE We sought to evaluate the screening modality and outcome of lung cancer occurring in heart transplant recipients (HTR) during a 21-year period. METHODS We conducted a retrospective review to investigate the incidence, risk factors, screening modality, treatment, and outcomes in HTR with lung cancer. We compared them with a case-matched HTR control group. RESULTS Out of 829 recipients of heart transplants, 19 cases of bronchogenic carcinoma were found either by routine chest X-ray (n = 10), chest computed tomographic (CT) scanning (n = 4), or by assessment of clinical symptoms (n = 5). The mean time from transplantation to bronchogenic carcinoma diagnosis was 68.8 +/- 42.4 months. A history of smoking was the only risk factor in HTR with bronchogenic carcinoma compared to their case-matched HTR control group ( P < 0.05). Of 18 patients with non-small cell lung cancer (NSCLC), 13 underwent surgery and 5 with advanced cancer underwent chemotherapy and/or radiotherapy. NSCLC was diagnosed by chest X-ray (n = 10), and 6 of these patients died after an average of 43.7 +/- 62.2 months following cancer detection. NSCLC was also diagnosed on the basis of clinical symptoms (n = 4), and 2 of these patients died after a mean follow-up of 9 +/- 4.2 months after cancer diagnosis. All 4 patients in whom cancer was detected by CT scan were alive at an average of 53.5 +/- 36.7 months following cancer detection. The survival rates did not differ between the study and control groups ( P = 0.5). CONCLUSIONS Optimal outcomes of treatment for primary lung cancer after heart transplantation seem to be related to early detection. A high proportion of deaths from NSCLC may be prevented by chest CT scan screening.
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Affiliation(s)
- S Mohammadi
- Department of Cardiothoracic Surgery, La Pitié Hospital, Paris, France.
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108
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Khelif A, Aoubiza B, Mohammadi S, Adibi A, Laude V. Complete band gaps in two-dimensional phononic crystal slabs. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 74:046610. [PMID: 17155195 DOI: 10.1103/physreve.74.046610] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Indexed: 05/12/2023]
Abstract
The propagation of acoustic waves in a phononic crystal slab consisting of piezoelectric inclusions placed periodically in an isotropic host material is analyzed. Numerical examples are obtained for a square lattice of quartz cylinders embedded in an epoxy matrix. It is found that several complete band gaps with a variable bandwidth exist for elastic waves of any polarization and incidence. In addition to the filling fraction, it is found that a key parameter for the existence and the width of these complete band gaps is the ratio of the slab thickness, d, to the lattice period, a. Especially, we have explored how these absolute band gaps close up as the parameter d/a increases. Significantly, it is observed that the band gaps of a phononic crystal slab are distinct from those of bulk acoustic waves propagating in the plane of an infinite two-dimensional phononic crystal with the same composition. The band gaps of the slab are strongly affected by the presence of cutoff frequency modes that cannot be excited in infinite media.
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Affiliation(s)
- A Khelif
- Institut FEMTO-ST, CNRS UMR 6174, Université de Franche-Comté, Besançon, France
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109
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Engqvist H, Botton GA, Couillard M, Mohammadi S, Malmström J, Emanuelsson L, Hermansson L, Phaneuf MW, Thomsen P. A novel tool for high-resolution transmission electron microscopy of intact interfaces between bone and metallic implants. J Biomed Mater Res A 2006; 78:20-4. [PMID: 16596587 DOI: 10.1002/jbm.a.30696] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A key feature in the understanding of the mechanisms of integration versus rejection of implanted materials is a deepened understanding of the elemental and molecular compositions of the interface zone between the surface of the synthetic man-made material and the biological components of tissue. Intact interfaces between metallic implants and tissues have not been able to image and analyse on the ultrastructural level with the common transmission electron microscopy (TEM) sample preparation techniques. By using focused ion beam microscopy for site-specific preparation of TEM samples, intact interfaces between metal implants and calcified tissue were imaged for the first time. The interface's elemental and crystallographic compositions were determined using energy dispersive X-ray mapping and electron diffraction. The developed technique fulfills a long-sought-for demand to correlate the surface properties of implanted metal prostheses with the fine structure and composition of preserved interfaces with tissues.
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Affiliation(s)
- H Engqvist
- The Angstrom Laboratory, Department of Materials Science, Uppsala University, Box 534, 751 21 Uppsala, Sweden.
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Talukder N, Shujaee K, Mohammadi S. Model studies on flow disturbance due to arterial stenosis. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)85556-9] [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: 10/24/2022]
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111
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Duning T, Deppe M, Kugel H, Mohammadi S, Knecht S. Fraktionelle Anisotropie als objektives quantitatives Maß altersbedingter Veränderungen des Gehirns. Akt Neurol 2004. [DOI: 10.1055/s-2004-833253] [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: 10/28/2022]
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Abstract
The aim of the present experimental study was to evaluate the tissue response to hafnium (Hf) a reactive metal closely related to titanium (Ti) and zirconium (Zr). Hf has not been previously evaluated as implant material in a biologic environment. In a first experiment, 21 machined Hf non-threaded implants (test) and 21 similar Ti implants (control) were inserted in the abdominal wall of 21 rats. Animals were sacrificed after 8 days (6 rats), 6 (7 rats) and 12 weeks (8 rats). In a second experiment, 18 rabbits received 18 Hf and 18 Ti threaded implants in their tibiae, one implant in each tibia. The rabbits were sacrificed after 6, 12 and 24 weeks (6 animals/time interval). The bulk metal of the abdominal wall implants, embedded together with the surrounding tissue, was electrolytically dissolved and semithin (1 microm) sections of the intact tissue-implant interface were evaluated by light microscopy (morphometry). Bone-implant contact and bone area within threads were evaluated in ground sections. In soft tissues, a fluid space containing predominantly monocytes/macrophages surrounded the abdominal implants at 8 days. At 6 and 12 weeks, a fibrous capsule, consisting of layers of macrophages and fibroblasts, surrounded the implants. Macrophages, including multinuclear giant cells, always formed the innermost layer in contact with the implant surface. No quantitative or qualitative difference in the tissue organization was detected between Ti and Hf implants. In rabbits, 6 weeks after insertion, the proximal two threads located within the cortical bone were filled with bone in contact with Hf and Ti. The distal threads contained bone marrow. After 12 and 24 weeks, mature bone was present in the proximal 3-4 implant threads. No statistically significant difference was found between Hf and Ti implants at any time periods. It is concluded that Hf is an interesting metal for biomedical applications in bone and soft tissue.
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Affiliation(s)
- S Mohammadi
- Institute of Anatomy and Cell Biology, Göteborg University, Göteborg, Sweden.
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113
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Rama A, Mohammadi S, Leprince P, Gandjbakhch I. A simple method for heart stabilization during off-pump multi-vessel coronary artery bypass grafting: surgical technique and short term results. Eur J Cardiothorac Surg 2001; 19:105-7. [PMID: 11163574 DOI: 10.1016/s1010-7940(00)00604-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Minimally invasive cardiac surgery regroups several technical options including small incision, video-assisted surgery and beating heart surgery but mechanical stabilization for off-pump multi-vessel coronary artery bypass grafting (CABG), remains a problem. We developed a simple method of stabilization with a fenestrated polytetrafluroethylene patch. Four sutures were passed deeply into the myocardium surrounding the anastomotic site. The sutures were then passed through the patch. Gentle traction on tied sutures, allowed immobilization and exposure in the selected area. This method which was carried in 95 patients, provides good stabilization for performing off-pump multi-vessel CABG in all cardiac territories.
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Affiliation(s)
- A Rama
- Department of Thoracic and Cardiovascular Surgery, La Pitié Hospital, 47 Boulevard de l'hôpital, 75013, Paris, France
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114
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Dorent R, Mohammadi S, Tezenas S, Silvaggio G, Ghossoub JJ, Leger P, Vaissier E, Leprince P, Carnot F, Riquet M, Pavie A, Gandjbakhch I. Lung cancer in heart transplant patients: a 16-year survey. Transplant Proc 2000; 32:2752-4. [PMID: 11134787 DOI: 10.1016/s0041-1345(00)01867-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- R Dorent
- Service de Chirurgie Cardio-Vasculaire et Thoracique, Hôpitaux Pitié-Salpêtrière, Paris, France
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115
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Mohammadi S, Rasmusson L, Göransson L, Sennerby L, Thomsen P, Kahnberg KE. Healing of titanium implants in onlay bone grafts: an experimental rabbit model. J Mater Sci Mater Med 2000; 11:83-89. [PMID: 15348051 DOI: 10.1023/a:1008936832689] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An experimental rabbit bone graft model for the study of bone formation and remodeling around titanium implants is described. A 2.5-cm long radius bone segment served as an onlay graft. Two commercially pure (c.p.) titanium implants were inserted into the bone graft prior to fixation to the inferior border of the mandibular base with osteosynthesis titanium screws. Each animal was operated twice, allowing follow-up periods of 6 weeks on one side and 6 months on the contralateral side. In order to study bone remodeling by means of fluoroscopy the animals received single injections of tetracyclin and alizarine complexone 2 weeks and 1 week, respectively, prior to sacrifice by perfusion fixation with glutaraldehyde. The bone and implants were excized en bloc, postfixed and embedded in plastic resin. Stained and unstained thin ground sections as well as microradiographed thick sections were produced for light microscopic morphometry and fluoroscopy. After 6 weeks, osteoclastic/osteoblastic activity was primarily observed in the graft-recipient contact area and in the intracortical compartment of the graft bone. New bone formation observed on the implant surface originated from the recipient site. The bone formation was evident also in the implant-graft interface. At 6 weeks the average bone fill of the implant threads was 28.4% which increased to 36.4% after 6 months as measured by morphometry. An average of 17.6% bony contact was measured after 6 weeks which increased to 29.7% 6 months after surgery. The graft bone had reduced in size from an average of 39.5% after 6 weeks down to 24.8% after 6 months (P \lt 0.05). It is concluded that the described experimental model can serve as a useful method for the study of implant healing in onlay grafts.
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Affiliation(s)
- S Mohammadi
- Institute of Anatomy and Cell Biology, Göteborg University, Sweden
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116
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Nori-Shargh D, Norouzi-Arasi H, Mohammadi S, Mirza M, Jaimand K. Volatile Component ofMentha longifolia(L.) Huds. from Iran. Journal of Essential Oil Research 2000. [DOI: 10.1080/10412905.2000.9712056] [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] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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118
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Mohammadi S, Klement R, Shchyolkina AK, Liquier J, Jovin TM, Taillandier E. FTIR and UV spectroscopy of parallel-stranded DNAs with mixed A*T/G*C sequences and their A*T/I*C analogues. Biochemistry 1998; 37:16529-37. [PMID: 9843419 DOI: 10.1021/bi981143p] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The infrared spectra of parallel-stranded (ps) hairpin duplexes with mixed A*T/G*C composition and either isolated or sequential G*C pairs were studied in comparison with antiparallel-stranded (aps) duplexes and a corresponding set of molecules with hypoxanthine as a G base analogue lacking the exocyclic amino group. The ps duplexes showed the characteristic bands for the C2=O2 and C4=O4 stretching vibrations of thymine residues in trans-Watson-Crick A*T pairing at 1683 and 1668 cm-1. The latter band was superimposed on the stretching vibration of the free C6=O6 group of guanine. Substitution of guanine by hypoxanthine inhibited the formation of ps hairpin duplexes whatever the sequence, demonstrating that in the H-bonding between G and C the 2-NH2 group is necessary for stabilizing all of the investigated ps duplexes. This result is in agreement with a model of trans-Watson-Crick G*C base pairs with two H-bonds [N2H2(G)-N3(C) and N1H(G)-O2(C)]. However, trans-Watson-Crick A*T and G*C base pairs with two H-bonds are not isomorphous, which may explain the decreased stability of the ps, but not the aps, duplexes upon increasing the number of A*T/G*C steps. Molecular modeling studies performed on two of the ps duplexes reveal the existence of propeller twist for avoiding a clash between the N2(G) and N4(C) amino groups, and favorable stacking of sequential G*C base pairs. The optimized hairpin ps duplexes invariably incorporated G*C base pairs with two H-bonds, regardless of the initial structures adopted for the force field calculations.
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Affiliation(s)
- S Mohammadi
- URA CNRS 1430, University of Paris XIII, Bobigny, France
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119
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Kahnberg KE, Rasmusson L, Mohammadi S. An experimental rabbit model for studying the healing of onlay bone grafts. Swed Dent J 1998; 22:15-21. [PMID: 9646389] [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] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An experimental rabbit model for studying the incorporation of onlay bone grafts is described. Bone grafts from radius served as the graft and were positioned beneath the mandibular basis. Six rabbits were used in the study and healing periods of 6 weeks and 6 months were used. Each animal was operated twice and in this way the grafts could be followed for six weeks on one side and for 6 months on the contralateral side of the mandible. Healing of the bone graft with bony union to the mandibular base with cortical bone in contact with cortical bone was encouraging. Remodelling of the graft was observed after 6 weeks but was even more pronounced after 6 months. After 6 weeks osteoclastic/osteoblastic activity was primarily observed in the graft-recipient contact area and in the intracortical compartment of the grafted bone. The resorption was most pronounced in the borderlines of the graft. It is concluded that the described experimental model can serve as a useful method for the study of onlay bone graft healing and interaction between implants and bone transplants.
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Affiliation(s)
- K E Kahnberg
- Department of Oral & Maxillofacial Surgery, Göteborg University, Sweden
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120
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Mohammadi S, Perrée-Fauvet M, Gresh N, Hillairet K, Taillandier E. Joint molecular modeling and spectroscopic studies of DNA complexes of a bis(arginyl) conjugate of a tricationic porphyrin designed to target the major groove. Biochemistry 1998; 37:6165-78. [PMID: 9558356 DOI: 10.1021/bi972964h] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To target selectively the major groove of double-stranded B DNA, we have designed and synthesized a bis(arginyl) conjugate of a tricationic porphyrin (BAP). Its binding energies with a series of double-stranded dodecanucleotides, having in common a central d(CpG)2 intercalation site were compared. The theoretical results indicated a significant energy preference favoring major groove over minor groove binding and a preferential binding to a sequence encompassing the palindrome GGCGCC encountered in the Primary Binding Site of the HIV-1 retrovirus. Spectroscopic studies were carried out on the complexes of BAP with poly(dG-dC) and poly(dA-dT) and a series of oligonucleotide duplexes having either a GGCGCC, CCCGGG, or TACGTA sequence. The results of UV-visible and circular dichroism spectroscopies indicated that intercalation of the porphyrin takes place in poly(dG-dC) and all the oligonucleotides. Thermal denaturation studies showed that BAP increased significantly the melting temperature of the oligonucleotides having the GGCGCC sequence, whereas it produced only a negligible stabilization of sequences having CCCGGG or TACGTA in place of GGCGCC. This indicates a preferential binding of BAP to GGCGCC, fully consistent with the theoretical predictions. IR spectroscopy on d(GGCGCC)2 indicated that the guanine absorption bands, C6=O6 and N7-C8-H, were shifted by the binding of BAP, indicative of the interactions of the arginine arms in the major groove. Thus, the de novo designed compound BAP constitutes one of the very rare intercalators which, similar to the antitumor drugs mitoxantrone and ditercalinium, binds DNA in the major groove rather than in the minor groove.
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Affiliation(s)
- S Mohammadi
- Laboratoire de Chimie Structurale et Spectroscopie Biomoléculaire (CNRS-URA 1430), Université Paris 13, Bobigny, France
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121
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Mohammadi S, Slama-Schwok A, Léger G, el Manouni D, Shchyolkina A, Leroux Y, Taillandier E. Triple helix formation and homologous strand exchange in pyrene-labeled oligonucleotides. Biochemistry 1997; 36:14836-44. [PMID: 9398205 DOI: 10.1021/bi971710t] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The orientations of the symmetrical third strands (G3A4G3) and (G3T4G3) within the triplexes (C3T4C3) - (G3A4G3) x (G3A4G3) and (C3T4C3) - (G3A4G3) x (G3T4G3) were investigated by fluorescence spectroscopy and thermal denaturation using pyrene-labeled oligodeoxynucleotides. In the two triplex structures, both parallel and antiparallel orientations of the third strand with respects to the purine Watson-Crick one were identified by means of pyrene excimer formation. The pyrene labels do not modify the melting temperature of the (C3T4C3) - (G3A4G3) x (G3T4G3) triplex but somewhat stabilize the corresponding duplex against thermal denaturation. The absorption melting profiles of the (C3T4C3) - (G3A4G3) x (G3A4G3) triplex are monophasic in agreement with previous reports. In contrast, the melting of this structure, when monitored by the pyrene excimer band, reveals a biphasic behavior. These data, together with kinetics measurements, strongly suggest exchange mechanisms between the homologous oligomers (G3A4G3), Hoogsteen, and Watson-Crick strands.
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Affiliation(s)
- S Mohammadi
- Laboratoire de Spectroscopie Biomoléculaire, URA CNRS 1430, UFR de Médecine et Biologie Humaine, Université Paris XIII, Bobigny, France
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122
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Escudé C, Mohammadi S, Sun JS, Nguyen CH, Bisagni E, Liquier J, Taillandier E, Garestier T, Hélène C. Ligand-induced formation of hoogsteen-paired parallel DNA. Chem Biol 1996; 3:57-65. [PMID: 8807829 DOI: 10.1016/s1074-5521(96)90085-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Based on molecular modeling studies, a model has been proposed for intercalation of triple-helix-specific ligands (benzopyridoindole (BPI) derivatives) into triple helices, in which the intercalating compounds interact mainly with the Hoogsteen-paired strands of the triple helix. We set out to test this model experimentally using DNA duplexes capable of forming parallel Hoogsteen base-paired structures. RESULTS We have investigated the possible formation of a parallel DNA structure involving Hoogsteen hydrogen bonds by thermal denaturation, FTIR spectroscopy and gel-shift experiments. We show that BPI derivatives bind to Hoogsteen base-paired duplexes and stabilize them. The compounds induce a reorganization from a non-perfectly matched antiparallel Watson- Crick duplex into a perfectly matched parallel Hoogsteen-paired duplex. CONCLUSIONS These results suggest that preferential intercalation of BPI derivatives in triple helices is due to their ability to interact specifically with the Hoogsteen-paired bases. The results are consistent with a model proposed on the basis of molecular modeling studies using energy minimization, and they open a new field of investigations regarding the biological relevance of Hoogsteen base-pairing.
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Affiliation(s)
- C Escudé
- Laboratoire de Biophysique, INSERM U201 CNRS URA481, Muséum National d'Histoire Naturelle, 43, rue Cuvier, 75231 Paris Cedex 05, France
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Mohler J, Weiss N, Murli S, Mohammadi S, Vani K, Vasilakis G, Song CH, Epstein A, Kuang T, English J. The embryonically active gene, unkempt, of Drosophila encodes a Cys3His finger protein. Genetics 1992; 131:377-88. [PMID: 1339381 PMCID: PMC1205012 DOI: 10.1093/genetics/131.2.377] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The unkempt gene of Drosophila encodes a set of embryonic RNAs, which are abundant during early stages of embryogenesis and are present ubiquitously in most somatic tissues from the syncytial embryo through stage 15 of embryogenesis. Expression of unkempt RNAs becomes restricted predominantly to the central nervous system in stages 16 and early 17. Analysis of cDNAs from this locus reveals the presence of five Cys3His fingers in the protein product. Isolation and analysis of mutations affecting the unkempt gene, including complete deletions of this gene, indicate that there is no zygotic requirement for unkempt during embryogenesis, presumably due to the contribution of maternally supplied RNA, although the gene is essential during post-embryonic development.
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Affiliation(s)
- J Mohler
- Barnard College, New York, New York 10027
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