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1.
BMC Nutr ; 8(1): 85, 2022 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-35996126

RESUMEN

BACKGROUND: Doctors are on the frontline of patient care and in an ideal position to provide nutritional advice, yet can feel ill-equipped to do so. The aim of this study was to explore the nutrition knowledge, skills and practice required for nutrition-competent medical graduates, and their role in providing nutrition advice and care, from the perspective of doctors with formal nutrition training. METHODOLOGY: We conducted an exploratory qualitative research study. A purposive sample of 12 medical doctors and students with formal nutrition training across Australia participated in in-depth semi structured interviews. Data were analysed thematically. RESULTS: There were four main themes identified: 1. Identifying the role of doctors in nutrition care; 2. Understanding the interrelatedness of the social determinants of health and nutrition status is key; 3. Optimising nutrition care through multidisciplinary collaboration; and 4. Providing evidence-based nutrition care. CONCLUSION: This exploratory study suggests that doctors consider that nutrition competent medical graduates require skills in referring to dietitians, an understanding and application of the social determinants of health, and practise applying multidisciplinary and evidence-based nutrition care.

2.
BJOG ; 129(6): 845-854, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34839565

RESUMEN

BACKGROUND: Pharmacological pain management options can relieve women's pain during labour and birth. Trials of these interventions have used a wide variety of outcomes, complicating meaningful comparisons of their effects. To facilitate better assessment of the effectiveness of labour pain management in trials and meta-analyses, consensus about key outcomes and the development of a core outcome set is essential. OBJECTIVE: To identify all outcomes used in studies of pharmacological pain management interventions during labour and birth. DESIGN: A review of systematic reviews and their included randomised controlled trials was undertaken. SEARCH STRATEGY: Cochrane CENTRAL was searched to identify all Cochrane systematic reviews describing pharmacological pain management options for labour and birth. Search terms included 'pain management', 'labour' and variants, with no limits on year of publication or language. SELECTION CRITERIA: Cochrane reviews and randomised controlled trials contained within these reviews were included, provided they compared a pharmacological intervention with other pain management options, placebo or no treatment. DATA COLLECTION AND ANALYSIS: All outcomes reported by reviews or trials were extracted and tabulated, with frequencies of individual outcomes reported. MAIN RESULTS: Nine Cochrane reviews and 227 unique trials were included. In total, 146 unique outcomes were identified and categorised into maternal, fetal, neonatal, child, health service, provider's perspective or economic outcome domains. CONCLUSIONS: Outcomes of pharmacological pain management interventions during labour and birth vary widely between trials. The standardisation of trial outcomes would permit the assessment of meta-analyses for best clinical practice. TWEETABLE ABSTRACT: Outcomes to measure pharmacological pain management options during labour are highly variable and require standardisation.


Asunto(s)
Dolor de Parto , Trabajo de Parto , Femenino , Humanos , Recién Nacido , Dolor de Parto/tratamiento farmacológico , Manejo del Dolor , Parto , Embarazo , Ensayos Clínicos Controlados Aleatorios como Asunto , Revisiones Sistemáticas como Asunto
3.
Lancet Reg Health West Pac ; 3: 100028, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34327381

RESUMEN

BACKGROUND: Quality care is essential for improving maternal and newborn health. Low- and middle-income Pacific Island nations face challenges in delivering quality maternal and newborn care. The aim of this review was to identify all published studies of interventions which sought to improve the quality of maternal and newborn care in Pacific low-and middle-income countries. METHODS: A scoping review framework was used. Databases and grey literature were searched for studies published between January 2000 and July 2019 which described actions to improve the quality of maternal and newborn care in Pacific low- and middle-income countries. Interventions were categorised using a four-level health system framework and the WHO quality of maternal and newborn care standards. An expert advisory group of Pacific Islander clinicians and researchers provided guidance throughout the review process. RESULTS: 2010 citations were identified and 32 studies included. Most interventions focused on the clinical service or organisational level, such as healthcare worker training, audit processes and improvements to infrastructure. Few addressed patient experiences or system-wide improvements. Enablers to improving quality care included community engagement, collaborative partnerships, adequate staff education and training and alignment with local priorities. CONCLUSIONS: There are several quality improvement initiatives in low- and middle-income Pacific Island nations, most at the point of health service delivery. To effectively strengthen quality maternal and newborn care in this region, efforts must broaden to improve health system leadership, deliver sustaining education programs and encompass learnings from women and their communities.

4.
Phys Rev Lett ; 104(16): 162501, 2010 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-20482043

RESUMEN

A measurement of the energy and spin of superdeformed states in 190Hg, obtained through the observation of transitions directly linking superdeformed and normal states, expands the number of isotopes in which binding energies at superdeformation are known. Comparison with neighboring nuclei shows that two-proton separation energies are higher in the superdeformed state than in the normal state, despite the lower Coulomb barrier and lower total binding energy. This unexpected result provides a critical test for nuclear models.

5.
Phys Rev Lett ; 96(11): 112503, 2006 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-16605815

RESUMEN

The shell structure underlying shape changes in neutron-rich nuclei near N = 28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in 38S and 40S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed 40S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

6.
Phys Rev Lett ; 95(18): 182501, 2005 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-16383897

RESUMEN

The excitation energy of the lowest-energy superdeformed band in 196Pb is established using the techniques of time-correlated gamma-ray spectroscopy. Together with previous measurements on 192Pb and 194Pb, this result allows superdeformed excitation energies, binding energies, and two-proton and two-neutron separation energies to be studied systematically, providing stringent tests for current nuclear models. The results are examined for evidence of a "superdeformed shell gap."

8.
J Periodontal Res ; 38(4): 355-61, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12828650

RESUMEN

BACKGROUND: Periodontitis is characterized by altered bone turnover, but local measurements are difficult. OBJECTIVES: The objective of this study was to develop a method to measure multiple markers of bone turnover from single samples collected at various bone surfaces of the periodontium, and to test the ratios of these markers against more traditional serum and gingival crevicular fluid (GCF) samples. MATERIALS AND METHODS: Fourteen subjects with untreated periodontitis were recruited for sampling serum, GCF (from sites > or = 5 mm probing depth that bled on probing) and washes of periodontal bone surfaces (adjacent interproximal, vestibular cortical and trabecular bone) with a novel irrigating device. All samples were analyzed for osteocalcin (OC, bone turnover marker; RIA), cross-linked N-telopeptide of type I collagen (NTx, bone resorption marker; ELISA) and albumin (Alb, serum protein; ELISA). Results were reported as ratios: OC/NTx to determine relative bone turnover, and OC/Alb or NTx/Alb to determine local OC or NTx production. RESULTS: The OC/NTx ratio was significantly higher (p < or = 0.05) in serum vs. GCF (OC undetectable), interproximal bone and cortical vestibular bone, but significantly lower than in trabecular vestibular bone. The OC/Alb ratio for serum was also statistically lower than for vestibular trabecular bone. The NTx/Alb ratio for serum was statistically lower than for GCF and all the bone wash test sites. The results indicated considerable local production of both OC and NTx. CONCLUSIONS: This system demonstrated that multiple markers of bone turnover can be harvested by irrigation from periodontal bone microenvironments. Bone turnover profiles from periodontal bone surfaces and GCF differed from systemic bone turnover profiles (serum) and may be valuable in tracking site-specific responses to disease or treatment.


Asunto(s)
Proceso Alveolar/metabolismo , Colágeno/análisis , Osteocalcina/análisis , Péptidos/análisis , Periodontitis/metabolismo , Adulto , Anciano , Albúminas/análisis , Análisis de Varianza , Biomarcadores/análisis , Biomarcadores/sangre , Colágeno/sangre , Colágeno Tipo I , Femenino , Líquido del Surco Gingival/química , Hemorragia Gingival/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Osteocalcina/sangre , Péptidos/sangre , Bolsa Periodontal/metabolismo , Periodontitis/sangre , Albúmina Sérica/análisis , Irrigación Terapéutica/instrumentación
9.
Phys Rev Lett ; 90(14): 142501, 2003 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-12731911

RESUMEN

Correlations of decays above and below isomeric states in the normally deformed minimum of 192Pb have been used to identify discrete transitions in the decay of the superdeformed (SD) band. The data establish the absolute excitation energy of the lowest observed SD level as 4.425 MeV. Extrapolation to the bandhead indicates that the excitation energy of the superdeformed well in 192Pb is 0.5 MeV lower than in the heavier isotope 194Pb. The results confirm the trend to decreasing excitation energy with decreasing neutron number predicted by both a macroscopic Strutinsky method approach and microscopic mean field calculations.

10.
Phys Rev Lett ; 86(13): 2746-9, 2001 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-11290029

RESUMEN

The linear polarization of gamma rays between excited and yrast superdeformed (SD) states in 190Hg was measured using the four-element CLOVER detectors of the EUROBALL IV gamma-ray spectrometer. This measurement shows in a model-independent way that the interband transitions which compete with the highly collective in-band quadrupole transitions are largely enhanced electric dipoles. Not only do these results represent the first measurement of the multipolarity of transitions between different SD states, but they also provide strong evidence for the interpretation of the structures in the SD minimum of the A approximately 190 region in terms of octupole excitations.

11.
J Neuropsychiatry Clin Neurosci ; 9(2): 259-66, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9144106

RESUMEN

The authors studied depression after focal subcortical lesions (SCLs) in 45 highly selected subjects. Secondary major depression (secondary MD) occurred in 20.0%, depressive disorder NOS (secondary DDNOS) in 4.4%, and secondary dysthymia in 0.0%. secondary MD after SCLs was associated with pallidal lesions (88.9%) and dystonia without geste antagonistique; subjects with secondary DDNOS had nigrotegmental lesions and parkinsonism. Depressive severity after SCLs correlated positively with severity of parkinsonism and dystonia. Pallidal lesions disrupting neurotransmitter systems and pallidothalamic and parietal input to the frontal lobe may lead to secondary MD, whereas nigrotegmental lesions may predispose to secondary MD forme fruste (secondary DDNOS) through disruption of mesocortical frontal or nigrostriatal dopamine tracts. Patients should be closely followed over several years for depression after such lesions, especially when accompanied by parkinsonism or dystonia without geste antagonistique.


Asunto(s)
Encefalopatías/complicaciones , Encefalopatías/patología , Trastorno Depresivo , Globo Pálido/patología , Trastornos Psicomotores/complicaciones , Sustancia Negra/patología , Encefalopatías/fisiopatología , Cuerpo Estriado/fisiopatología , Trastorno Depresivo/complicaciones , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/etiología , Lóbulo Frontal/fisiopatología , Humanos , Enfermedad de Parkinson Secundaria/complicaciones , Escalas de Valoración Psiquiátrica , Índice de Severidad de la Enfermedad
12.
J Mol Cell Cardiol ; 29(2): 849-54, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9140842

RESUMEN

We have previously shown that, while ischemic preconditioning and cardioplegia afford similar protection against injury during ischemia and reperfusion, this protection is not additive. However, it is not known whether the same applies when the delivery of cardioplegia is suboptimal, such as may occur in the case of a coronary stenosis. To investigate the protective effect of cardioplegia v preconditioning when the delivery of cardioplegia is impaired, isolated rat hearts were subjected to 40 min of global ischemia followed by 40 min of reperfusion. Seven groups of hearts (1 g wet wt) were studied (n = 8/group): Group 1: controls with unprotected ischemia (no intervention): Group 2: in which only 0.2 ml of the St Thomas' cardioplegic solution was administered (2 min) prior to ischemia: group 3: in which the volume of cardioplegic solution was increased to 0.5 ml: Group 4: received 1.0 ml of cardioplegia: Group 5: received 2.0 ml of cardioplegia: Group 6: were subjected to ischemic preconditioning (3 min ischemia, 3 min reperfusion, 5 min ischemia, 5 min reperfusion) prior to ischemia: and Group 7: in which ischemic preconditioning and cardioplegia (1.0 ml) were used in combination. The mean postischemic recovery of left ventricular developed pressure (LVDP), expressed as a percentage of its pre-ischemic value, was 33 +/- 3% in the control group: this was significantly improved (P < 0.05) in hearts receiving 2.0 ml of cardioplegia (59 +/- 5%), whereas volumes of 0.2, 0.5 or 1.0 ml of cardioplegia afforded no significant protection (recoveries of LVDP were 32 +/- 6%, 37 +/- 5% and 37 +/- 5%, respectively). Preconditioning alone and the combination of preconditioning plus 1.0 ml of cardioplegia afforded similar protection (57 +/- 3%, and 58 +/- 3%, P < 0.05 v controls). At the end of reperfusion, left ventricular end-diastolic pressure (LVEDP) was substantially increased in control hearts (57 +/- 3 mmHg): it was decreased in the groups receiving 2.0 ml of cardioplegic solution (40 +/- 5 mmHg; P < 0.05 v control group), but not in the group receiving 0.2, 0.5 or 1.0 ml of cardioplegic solution (59 +/- 4, 55 +/- 3 and 54 +/- 4 mmHg, respectively). Again, preconditioning alone or preconditioning plus 1.0 ml of cardioplegia afforded similar good protection (39 +/- 1 mmHg and 37 +/- 2 mmHg, respectively). A similar pattern was observed for the post-ischemic recovery of coronary flow. Under conditions where the delivery of cardioplegia is impaired (< 2.0 ml/g myocardium) preconditioning alone or preconditioning in combination with cardioplegia is more protective that cardioplegia alone. These results may be of clinical interest because most patients undergoing surgery for ischemic heart disease suffer from severe coronary artery lesions that may prevent the delivery of sufficient cardioplegic solution to ensure maximum protection.


Asunto(s)
Paro Cardíaco Inducido , Precondicionamiento Isquémico Miocárdico , Animales , Soluciones Cardiopléjicas/uso terapéutico , Circulación Coronaria , Técnicas In Vitro , Masculino , Isquemia Miocárdica , Reperfusión Miocárdica , Ratas , Ratas Wistar , Presión Ventricular
13.
Artículo en Inglés | MEDLINE | ID: mdl-9118200

RESUMEN

We studied subjects with focal subcortical lesions (SCLs) and investigated the frequency of pallidal lesions in secondary major depression (secondary MD) presenting after but not before lesion onset. Forty-five subjects were selected for focal subcortical lesions (SCLs) from 10,000 hospital magnetic resonance imaging (MRI) films. SCLs were ascertained by neuroradiologic criteria. Major depression was ascertained by DSM-III, -III-R, and -IV criteria. We compared subjects with secondary MD to SCL subjects lacking life histories of mood disorders and investigated the lesion distribution among pallidal subregions evident on MRI. We further tested an association between pallidal lesions and secondary MD. Pallidal lesions were present in eight (89%) of nine subjects with secondary MD and 13 (59%) of 22 controls. Left posterior pallidal lesions occurred in four (44%) of the nine subjects with secondary MD and two (9%) of the 22 controls (one-tailed Fisher's exact test p = 0.043). Demographic and other factors did not differ between subjects with secondary MD and controls (using Fisher's exact test or Mann-Whitney U test as statistically appropriate). These data, of small sample size and requiring confirmation, suggest the possibility that abnormal pallidal function may contribute to depressive pathophysiology, perhaps by influencing basal ganglia-thalamocortical mood circuits. Left-lateralized circuits in the posterior pallidum may be of particular relevance. The left pallidal association is compatible with previous findings in poststroke depression. Patients with left pallidal lesions may deserve close monitoring for secondary MD after subcortical lesions.


Asunto(s)
Trastorno Depresivo/fisiopatología , Lateralidad Funcional , Globo Pálido/fisiopatología , Anciano , Trastorno Depresivo/diagnóstico , Femenino , Lóbulo Frontal , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas , Escalas de Valoración Psiquiátrica
14.
Br J Orthod ; 21(2): 161-7, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-8043564

RESUMEN

In the past, vertical intrusive movement of teeth has been considered difficult and most routine clinical vertical movement of teeth has been confined to extrusion. It has been suggested that attempts at intrusion may result in an increased incidence of root resorption and also in occasional devitalization. The displacement and resulting stress fields associated with such treatment can be successfully studied using the finite element method. In the case being considered initial movements are known to be small; therefore, the assumption in the study that the material behaves linear-elastically is considered to be reasonable. This study of vertical tooth movement demonstrated that the maximum cervical margin stress in the periodontal ligament was 0.0046 N/mm2, whilst the highest apical stress was 0.00205 N/mm2 when intrusive and extrusive forces of 1 Newton were applied to the buccal surface of the crown of a tooth model. These stresses were evaluated in the light of previous studies and found to be within the suggested clinical optimum level. However, the periodontal stress distribution following orthodontic loading within this three-dimensional finite element model was found to be highly complex.


Asunto(s)
Diente Canino/fisiología , Modelos Biológicos , Ligamento Periodontal/fisiología , Técnicas de Movimiento Dental , Análisis del Estrés Dental , Elasticidad , Humanos , Estrés Mecánico , Resistencia a la Tracción , Raíz del Diente/fisiología
15.
Gen Pharmacol ; 25(2): 345-54, 1994 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8026735

RESUMEN

1. The role of adenosine in the control of coronary vessel tone was studied using two guinea-pig hearts in series. Vasodilatory mediator(s) released by the donor heart were assayed by the recipient heart. 2. Adenosine deaminase reduced the activity of vasodilatory mediator(s) released by histamine and isoprenaline by 58.0 +/- 14.4% and 80.5 +/- 5.9% respectively; responses to exogenous adenosine were abolished. 3. Adenosine deaminase added to the donor perfusate supplying the recipient heart caused a significant increase in basal perfusion pressure. 4. Our results suggest adenosine is not the sole mediator of vasodilation in stressed hearts and additionally unstressed hearts appear to release a basal vasodilatory level of adenosine.


Asunto(s)
Adenosina/metabolismo , Corazón/efectos de los fármacos , Histamina/farmacología , Isoproterenol/farmacología , Miocardio/metabolismo , Vasodilatación/fisiología , Acetilcolina/farmacología , Adenosina Desaminasa/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Circulación Coronaria/efectos de los fármacos , Cobayas , Frecuencia Cardíaca/efectos de los fármacos , Técnicas In Vitro , Masculino , Contracción Miocárdica/efectos de los fármacos , Vasodilatación/efectos de los fármacos
16.
Can J Physiol Pharmacol ; 72(2): 152-60, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8050056

RESUMEN

The role of endogenous adenosine during the beta-adrenoceptor responses to isoprenaline of guinea-pig isolated cardiac preparations was examined. Insignificant effects of adenosine deaminase (0.3 U.mL-1) on cumulative concentration--response curves for isoprenaline on isolated left and right atria and papillary muscles indicated a negligible depressant effect of endogenous adenosine during these responses. The increase in force of contraction to an infusion of isoprenaline (14 nM) in perfused spontaneously beating hearts rapidly waned while the infusion continued, whereas the increase in rate of contraction remained constant throughout the infusion. The degree of fade was less in paced preparations (5 Hz), indicating that it was only in part due to the rate increase exerting some mechanical constraint on the force of contraction. The P1-purinoceptor antagonist 8-phenyltheophylline (12 microM) and adenosine deaminase (0.3 U.mL-1) did not enhance the peak responses to the isoprenaline infusion. The fade of the inotropic response in both spontaneous and paced hearts was also not attenuated by the presence of 8-phenyltheophylline or adenosine deaminase. The fade was not, therefore, due to release of endogenous adenosine exerting a depressant effect. Whether this declining inotropic response represents a form of rapid desensitization remains to be determined.


Asunto(s)
Adenosina/fisiología , Isoproterenol/farmacología , Contracción Miocárdica/efectos de los fármacos , Contracción Miocárdica/fisiología , Adenosina Desaminasa/fisiología , Animales , Función del Atrio Izquierdo/efectos de los fármacos , Función del Atrio Derecho/efectos de los fármacos , Cobayas , Técnicas In Vitro , Masculino , Músculos Papilares/efectos de los fármacos , Teofilina/análogos & derivados , Teofilina/farmacología
17.
Eur J Cancer ; 30A(6): 746-51, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7917531

RESUMEN

Data gathered on 62 patients with soft tissue sarcoma of an extremity, treated in entirety by an experienced multidisciplinary sarcoma group, were analysed. With a philosophy of emphasising attainment of histologically negative margins at carefully planned limb sparing surgery, combined with either pre-operative or postoperative radiation therapy, a crude local control rate of 95% (59 of 62 patients) at a minimum of 24 months follow-up was obtained. Of 9 patients with microscopically positive margins after definitive surgery, 8 had undergone maximal resection compatible with preservation of function. One of these 9 failed locally, indicating that radiation therapy is effective in eradicating microscopic disease in this tumour. The excellent local control obtained with limb-sparing surgery in this series justifies early referral of patients with these uncommon cancers to an experienced multidisciplinary unit. 26 patients (42%) failed systemically at a minimum of 24 months follow-up, and 19 (30.6%) died of their disease, confirming the need for effective systemic therapy in soft tissue sarcoma. Tumours greater than 10 cm in diameter had a greater risk of systemic relapse.


Asunto(s)
Sarcoma/radioterapia , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/radioterapia , Neoplasias de los Tejidos Blandos/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sarcoma/mortalidad , Neoplasias de los Tejidos Blandos/mortalidad
18.
Appl Opt ; 33(21): 4714-8, 1994 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-20935842

RESUMEN

Fine-scale interference fringes that decorate caustics produced with white light appear black and white with high contrast. This is surprising, as the elementary expectation, supported by theory and computer simulation, is that the fringes should be highly colored. The fringe separation is several arc minutes and therefore close to the resolution limit of the eye. Under magnification (even of a photograph), the colors are revealed. Therefore black-and-white fringes are an illusion, giving a dramatic naked-eye illustration of the fact that the angular resolution of the visual system is better for luminance than for color.

19.
Am J Physiol ; 263(2 Pt 1): L168-76, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1514641

RESUMEN

We have identified the presence of functional prostaglandin H synthase (PGH synthase, E.C. 1.14.99.1, or cyclooxygenase) within canine mast cell granules by demonstrating the generation of prostaglandin (PG) D2 from isolated and purified granules incubated with substrate as arachidonic acid or stimulated with calcium ionophore, A23187. This confirms the presence of both enzyme and substrate within the granule. Localization of PGH synthase to the granule was confirmed by immunoblotting of the pure granule preparation and by immunocytochemistry using the whole cell. In functional studies, colchicine, a microtubule polymerization inhibitor, caused a fall of up to 70%, both in the amount of histamine released and in the amount of PGD2 generated. This suggests either that functional PGH synthase is closely associated and coactivated with granules or that there is an independent association of this enzyme with the microtubule system. Release of the preformed and newly formed mediators of the mast cell appear to be closely linked, and prevention of degranulation may therefore attenuate the effects of both classes of mediators.


Asunto(s)
Gránulos Citoplasmáticos/metabolismo , Mastocitos/metabolismo , Prostaglandina D2/biosíntesis , Prostaglandina-Endoperóxido Sintasas/metabolismo , Animales , Colchicina/farmacología , Perros , Immunoblotting , Inmunohistoquímica , Mastocitos/ultraestructura , Microscopía Electrónica
20.
Angle Orthod ; 62(1): 15-22, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1554158

RESUMEN

The quantification of stress in the periodontal ligament is an important concept, as stress in this tissue is transmitted to the alveolus, with subsequent bone remodelling and tooth movement. A number of clinical studies have suggested figures for such an optimal stress range. This study makes use of a finite element technique to determine the stress induced in the periodontal ligament in three dimensions when a maxillary canine tooth is subjected to an orthodontic force similar to that produced by an edgewise appliance. The maximum stress induced at the cervical margin of the periodontal ligament was 0.072 N/mm2, while the maximum stress induced at the level of the apical foramen was 0.0038 N/mm2. These results are discussed in the light of known clinical experience and compared with the stresses produced in the periodontal ligament by other orthodontic forces. The findings would suggest that even with 'perfect' edgewise mechanics it would be difficult to obtain canine movement by pure translation or 'bodily movement.'


Asunto(s)
Diente Canino/fisiología , Aparatos Ortodóncicos , Ligamento Periodontal/fisiología , Técnicas de Movimiento Dental/instrumentación , Proceso Alveolar/fisiología , Simulación por Computador , Esmalte Dental/fisiología , Dentina/fisiología , Elasticidad , Humanos , Modelos Biológicos , Soportes Ortodóncicos , Alambres para Ortodoncia , Estrés Mecánico , Resistencia a la Tracción , Raíz del Diente/fisiología
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