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1.
Nurs Leadersh (Tor Ont) ; 32(4): 74-80, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32083533

RESUMEN

This article describes the experience of adopting the NCLEX-RN as an entry-to-practice exam among francophone baccalaureate nursing students in New Brunswick, Canada. The journey between 2012 and now has been difficult, and nursing leadership was necessary to inform key stakeholders regarding the inequities faced by francophone nursing students and to bring about change. Here is a description of the arduous work done by a group of concerned nurses (active and retired) to advocate for the rights of francophone nursing students.


Asunto(s)
Barreras de Comunicación , Evaluación Educacional/normas , Licencia en Enfermería/normas , Competencia Clínica/normas , Competencia Clínica/estadística & datos numéricos , Bachillerato en Enfermería/normas , Bachillerato en Enfermería/estadística & datos numéricos , Evaluación Educacional/métodos , Evaluación Educacional/estadística & datos numéricos , Humanos , Licencia en Enfermería/estadística & datos numéricos , Licencia en Enfermería/tendencias , Nuevo Brunswick , Estudiantes de Enfermería/estadística & datos numéricos
2.
J Tissue Eng Regen Med ; 8(8): 652-63, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23161724

RESUMEN

Human mesenchymal stem cells (MSCs), which can generate both osteoblasts and chondrocytes, represent an ideal resource for orthopaedic repair using tissue-engineering approaches. One major difficulty for the development of osteochondral constructs using undifferentiated MSCs is that serum is typically used in culture protocols to promote differentiation of the osteogenic component, whereas existing chondrogenic differentiation protocols rely on the use of serum-free conditions. In order to define conditions which could be compatible with both chondrogenic and osteogenic differentiation in a single bioreactor, we have analysed the efficiency of new biphasic differentiation regimes based on transient serum exposure followed by serum-free treatment. MSC differentiation was assessed either in serum-free medium or with a range of transient exposure to serum, and compared to continuous serum-containing treatment. Although osteogenic differentation was not supported in the complete absence of serum, marker expression and extensive mineralization analyses established that 5 days of transient exposure triggered a level of differentiation comparable to that observed when serum was present throughout. This initial phase of serum exposure was further shown to support the successful chondrogenic differentiation of MSCs, comparable to controls maintained in serum-free conditions throughout. This study indicates that a culture based on temporal serum exposure followed by serum-free treatment is compatible with both osteogenic and chondrogenic differentiation of MSCs. These results will allow the development of novel strategies for osteochondral tissue engineering approaches using MSCs for regenerative medicine.


Asunto(s)
Diferenciación Celular , Células Madre Mesenquimatosas/citología , Suero/metabolismo , Biomarcadores/metabolismo , Calcio/metabolismo , Proliferación Celular , Células Cultivadas , Condrogénesis , Humanos , Cinética , Células Madre Mesenquimatosas/ultraestructura , Minerales/metabolismo , Osteogénesis
3.
Int J Nurs Pract ; 15(6): 502-9, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19958404

RESUMEN

This paper describes the enhancement of cultural competence through trans-Atlantic rural community experiences of European and Canadian nursing students using critical incident technique (CIT) as the students' reflective writing method. The data generated from 48 students' recordings about 134 critical incidents over a 2-year project were analysed by qualitative content analysis. Five main learning categories were identified as: cross-cultural ethical issues; cultural and social differences; health-care inequalities; population health concerns; and personal and professional awareness. Four emergent cultural perspectives for the health sector that became apparent from the reflections were: health promotion realm; sensitivity to social and cultural aspects of people's lives; channels between the health sector and society; cultural language and stories of local people. CIT was successfully used to foster European and Canadian undergraduate students' cultural reflections resulting in considerations and suggestions for future endeavours to enhance cultural competence in nursing education.


Asunto(s)
Competencia Cultural , Estudiantes de Enfermería , Canadá , Ética en Enfermería , Europa (Continente)
4.
Clin Genet ; 68(3): 255-61, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16098015

RESUMEN

Most UK genetics centres offering predictive testing for hereditary non-polyposis colorectal cancer (HNPCC) use an extended counselling protocol originally developed for Huntington's disease. Shortened counselling may be more appropriate in the context of treatable genetic conditions such as HNPCC. Twenty-six high-risk individuals were randomized to extended genetic counselling (two sessions of education and reflection held 1 month apart) or shortened genetic counselling (a single educational session) prior to HNPCC testing. Prospective questionnaires, interviews and transcripts of counselling sessions were analysed. Participants were unsure what to expect prior to genetic counselling and had already decided to undergo genetic testing. There was no evidence of psychological harm caused by shortened genetic counselling, with a high level of satisfaction with the counselling received in both groups. Reflective counselling occurred in both groups but was framed in terms of practical action and information. Participants expressed differing preferences for the level of information received. This exploratory study indicates that shortened genetic counselling may be an appropriate means of supporting decisions already made by individuals about HNPCC testing. However, participants would benefit from preparatory information to help them reflect on issues not previously considered, which can then be explored more fully as part of a tailored counselling approach.


Asunto(s)
Neoplasias Colorrectales Hereditarias sin Poliposis/psicología , Asesoramiento Genético/métodos , Adulto , Toma de Decisiones , Femenino , Asesoramiento Genético/psicología , Humanos , Entrevistas como Asunto , Masculino , Estrés Psicológico , Encuestas y Cuestionarios
5.
Med Image Anal ; 9(2): 123-32, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15721228

RESUMEN

In this paper, we propose a new approach to simulate the small intestine in a context of laparoscopic surgery. The ultimate aim of this work is to simulate the training of a basic surgical gesture in real-time: moving aside the intestine to reach hidden areas of the abdomen. The main problem posed by this kind of simulation is animating the intestine. The problem comes from the nature of the intestine: a very long tube which is not isotropically elastic, and is contained in a volume that is small when compared to the intestine's length. It coils extensively and collides with itself in many places. To do this, we use a layered model to animate the intestine. The intestine's axis is animated as a linear mechanical component. A specific sphere-based model handles contacts and self-collisions. A skinning model is used to create the intestine's volume around the axis. This paper discusses and compares three different representations for skinning the intestine: a parametric surface model and two implicit surface models. The first implicit surface model uses point skeletons while the second uses local convolution surfaces. Using these models, we obtained good-looking results in real-time. Some videos of this work can be found in the online version at doi: 10.1016/j.media.2004.11.006 and at www-imagis.imag.fr/Publications/2004/FLAMCFC04.


Asunto(s)
Gráficos por Computador , Interpretación de Imagen Asistida por Computador/métodos , Intestinos/patología , Intestinos/cirugía , Modelos Biológicos , Cirugía Asistida por Computador/métodos , Interfaz Usuario-Computador , Algoritmos , Simulación por Computador , Sistemas de Computación , Humanos , Aumento de la Imagen/métodos , Imagenología Tridimensional/métodos , Telemedicina/métodos
6.
Fam Cancer ; 3(1): 55-9, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15131407

RESUMEN

Increasing demands upon specialist cancer genetics services have resulted in a need to explore alternative means of delivering genetic risk information to individuals at low-risk of familial cancer. This pilot study investigates patient satisfaction with a letter to low and moderate risk individuals notifying them of their risk. Sixty-six people completed a questionnaire designed to measure satisfaction with the way they had been notified of their cancer risk. Two key findings emerge from the data: first of all, whilst many respondents indicated overall satisfaction with the risk letter, a substantial number wanted more information about their risk; and secondly, low-risk individuals in this study are less reassured by and less satisfied with the risk letter than those at moderate risk. The optimal service provision for delivery of genetic risk information is likely to be one which can best respond to individual differences in information-seeking, distress and risk comprehension. There is a need therefore, for a randomised control trial to compare the effectiveness of a risk notification letter with more traditional telephone risk counselling and the implications of each mode of delivery upon the resources of specialist cancer genetics services.


Asunto(s)
Neoplasias de la Mama/genética , Neoplasias Colorrectales/genética , Predisposición Genética a la Enfermedad , Educación del Paciente como Asunto/métodos , Adulto , Anciano , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/patología , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/patología , Correspondencia como Asunto , Femenino , Asesoramiento Genético , Humanos , Masculino , Informática Médica , Persona de Mediana Edad , Estadificación de Neoplasias , Satisfacción del Paciente/estadística & datos numéricos , Linaje , Proyectos Piloto , Estudios Retrospectivos , Medición de Riesgo , Apoyo Social , Encuestas y Cuestionarios , Gales/epidemiología
7.
Clin Biomech (Bristol, Avon) ; 16(8): 710-3, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11535354

RESUMEN

OBJECTIVE: To determine the effect of error in the location of the anterior superior iliac spine, and the centres of the patella and tibial tuberosity, on the measured value of the quadriceps angle. BACKGROUND: The quadriceps angle is said to be relevant in the etiology and management of patello-femoral pain. However, the issues around measurement accuracy have not been reported. METHODS: Errors between 1 and 5 mm were introduced to the medial/lateral and vertical co-ordinate data describing the position of the anterior superior iliac spine, the centre of the patella and the centre of the tibial tuberosity, and the effect on the quadriceps angle determined. RESULTS: Errors between 1 and 5 mm in the medial/lateral location of the centre of the patella produced changes in the quadriceps angle between 1.13 degrees and 5.53 degrees. Errors between 1 and 5 mm in the medial/lateral location of the tibial tuberosity produced changes in the quadriceps angle between 1.02 degrees and 5.18 degrees. CONCLUSIONS: The quadriceps angle is highly sensitive to error in the definition of the centre of the patella and tibial tuberosity. As an approximation, these centres need to be defined with an accuracy of less than 2 mm if the error in the quadriceps angle is to remain below 5 degrees. RELEVANCE: Until a clinical technique for measuring the quadriceps angle with a high level of accuracy is developed, the clinical use of the quadriceps angle is questionable.


Asunto(s)
Articulación de la Rodilla/anatomía & histología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Rótula/anatomía & histología , Tibia/anatomía & histología
8.
J Med Genet ; 37(3): 192-6, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10699055

RESUMEN

Randomised controlled trials allow comparisons to be made between different models of service delivery, but have not been used in the field of clinical genetics. With the advent of clinical governance, the evidence provided by such trials will be increasingly important in informing and shaping clinical genetics practice. The TRACE project (Trial of genetic assessment in breast cancer) is a randomised controlled trial of genetic assessment for women who are at increased risk of breast cancer because of their family history. The absence of cancer genetics service provision in Wales before this study gave a window of opportunity in which this important trial could be conducted. The present paper describes how TRACE will provide crucial evidence regarding the psychosocial as well as resource implications of adding individualised genetic assessment, genetic counselling, and (where appropriate) gene testing to typical advice and surveillance from a hospital breast clinic. In addition, it is anticipated that TRACE will represent a model for future trials of service delivery in the increasing number of complex genetic disorders where evidence on the economic implications of screening and management is currently limited.


Asunto(s)
Neoplasias de la Mama/genética , Predisposición Genética a la Enfermedad , Pruebas Genéticas , Adulto , Proteína BRCA2 , Estudios de Evaluación como Asunto , Femenino , Genes BRCA1 , Asesoramiento Genético , Humanos , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Medición de Riesgo , Factores de Transcripción/genética
9.
Breast ; 9(6): 343-8, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14965759

RESUMEN

Breast cancer is a rare condition in males. There is a dearth of information about the psychological and social impact of this condition. Data from six in-depth interviews with men who had breast cancer identified seven major issues. These were associated with delay in diagnosis, shock, stigma, body image, causal factors, the provision of information and emotional support. The findings from this small study suggest that there are psychological and social factors for men diagnosed with breast cancer which have implications for their care and management. The recommendations arising from this study are the development of a structured education programme aimed at all primary health-care professionals; with availability of pre and postoperative gender-specific information to alleviate the potential psychological problems associated with the diagnosis; and provision of appropriate support/counselling services for partners of patients.

10.
J AAPOS ; 3(6): 341-3, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10613577

RESUMEN

BACKGROUND: Optical penalization (OP) has previously been shown to successfully maintain vision in amblyopic eyes of older children when patching compliance is poor and when vision decreases once patching is discontinued. This study shows that the final vision in optically penalized eyes is often better than the vision obtained after patching alone. SUBJECTS AND METHODS: During the 5-year period from January 1992 to February 1997, 28 children aged between 3.7 and 8.2 years (average age, 6.5+/-1.1 years) were optically penalized for an average of 1.5+/-0.75 years. The maximum length of penalization was 3.3 years, whereas the minimum time was 6 months. There were 21 children with strabismic amblyopia and 7 children with anisometropic amblyopia. All 28 children had worn a patch to achieve their best visual levels and then had shown a loss of best vision when occlusion was stopped. Patching was usually resumed and continued until the previous best vision was obtained; at this point OP was started to "maintain" vision. Eighteen of the 28 children have discontinued penalization and have been followed up an average of 1(1/2) years. RESULTS: Twenty-six (93%) of the 28 patients showed an increase in best vision from that found at the conclusion of patching, and 2 patients maintained their vision at the initial level. The average visual acuity at the start of penalization was 20/50 (0.42+/-0.11 logarithm of the minimum angle of resolution [log MAR]). Final average visual acuity was 20/27 (0.15+/-0.12 log MAR). The average increase in vision was nearly 3 lines or 0.27+/-0.12 log MAR. CONCLUSION: OP alone (without the use of pharmacologic agents such as atropine) not only maintains vision after patching therapy, but also appears to improve the final visual outcome.


Asunto(s)
Ambliopía/terapia , Anteojos , Óptica y Fotónica , Privación Sensorial , Ambliopía/complicaciones , Anisometropía/complicaciones , Niño , Preescolar , Femenino , Humanos , Masculino , Refracción Ocular , Estudios Retrospectivos , Estrabismo/complicaciones , Resultado del Tratamiento , Agudeza Visual
11.
J Genet Couns ; 8(5): 289-99, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26142375

RESUMEN

Genetic testing is now feasible for a growing number of cancers. Although the implications for unaffected relatives have been widely described, the impact of the tests on affected individuals are often not recognized. We present and discuss four cases that highlight some of the issues-for example, feelings of guilt and anxiety, intrafamilial conflict, and support needs-that may arise in testing affected individuals. We offer some suggestions to aid in the approach to such testing.

12.
Mil Med ; 163(5): 278-82, 1998 May.
Artículo en Inglés | MEDLINE | ID: mdl-9597841

RESUMEN

From the experience of a U.S. Army Air Defense Artillery "battalion-plus" task force serving a 6-month rotation in the Kingdom of Saudi Arabia, we compiled the requirements for specialty consultations on deployed personnel in the predeployment screening phase, during deployment (including both inpatient hospitalizations and medical evacuations), and immediately upon return to home station. We required a wide variety of specialty expertise. In every phase of the operation, we consulted orthopedic surgery most often. Nonsurgical and surgical specialists were consulted in roughly equal numbers. Almost every field of adult medicine was represented in our sample. The distribution of consultations across specialties differs from what would be expected in combat but is similar to that seen in the few other studies of comparable populations. Excellent host nation support allowed us to use specialty expertise to an almost ideal extent. These data represent the most complete "snapshot" that has been taken of the requirements for specialty medical consultations in a military operation other than war (MOOTW). They demonstrate that under MOOTW conditions, even a healthy Army population requires the assistance of a full panel of medical specialties. They should serve as a benchmark for planners estimating the medical specialty needs that the Army must provide. Military medicine must provide access to essentially all medical specialties for personnel deployed under MOOTW conditions, whether through host nation support, telemedicine, or medical evacuation.


Asunto(s)
Necesidades y Demandas de Servicios de Salud/estadística & datos numéricos , Medicina/estadística & datos numéricos , Medicina Militar/organización & administración , Derivación y Consulta/estadística & datos numéricos , Especialización , Adulto , Femenino , Investigación sobre Servicios de Salud , Humanos , Masculino , Arabia Saudita , Estados Unidos , Guerra
13.
Prim Care Update Ob Gyns ; 5(4): 154, 1998 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-10838286

RESUMEN

Objective: The objective of this study was to determine what changes occur in pulmonary function testing in pregnant women who smoke versus nonsmokers.Methods: This was a prospective study. Pregnant women were recruited in all trimesters of pregnancy. A total of 34 women (15 smokers, 19 nonsmokers) were recruited. Measurements of forced vital capacity (FVC), forced expiratory volume in one second (FEVI), the ratio of FEVI to FVC, and maximum voluntary ventilation (MVV) were obtained.Results:Conclusions: This study confirms other studies that have seen no significant changes in FVC, FEVI, FEVI/FVC in pregnant smokers and nonsmokers. A significant worsening in MVV was seen in pregnant women who smoke. The pathophysiologic impact of this effect is unclear. However, since MVV is a measure of the bellows action of the chest, this may lead to a decrease in oxygenation during the active phase and the second stage of labor. This may lead to more abnormal fetal monitoring strips and possibly lower Apgar scores. Further investigation will be necessary to clarify the effects on pregnancy of lower MVV in patients who smoke.

14.
Microsc Res Tech ; 38(5): 529-43, 1997 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-9376658

RESUMEN

Asphalt cements are often regarded as a colloidal system containing several hydrocarbon constituents: asphaltenes, resins, and oils. The high molecular weight asphaltene particles are considered to be covered in a sheath of resins and dispersed in the lower molecular weight oily medium [Whiteoak (1990) The Shell Bitumen Handbook (Shell Bitumen UK, Riversdell House, Surrey, UK)]. However, the exact arrangement of the asphaltene particles within the oily phase will vary depending on the relative amounts of resin, asphaltene, and oils. It is this arrangement and the degree of association between asphaltene particles that govern the rheological properties of the cement [Simpson et al. (1961) J. Chem. Eng. Data 6:426-429; Whiteoak (1990)]. Here we report for the first time the observation of a three-dimensional network of asphaltene strands within straight, polymer-modified, and aged asphalt cements. While the existence of a asphaltene/resin micelle network has been proposed in previous studies [Whiteoak (1990)], direct observation has not been reported. The network is expected to greatly influence the rheological properties of the asphalt binder and ultimately the properties of asphalt concretes. In situ fracture studies of asphalt cement/aggregate composites indicate a possible correlation between the network structure and adhesion between the cement binder and aggregate.


Asunto(s)
Hidrocarburos/análisis , Hidrocarburos/química , Microscopía Electrónica de Rastreo , Polímeros
15.
Acta Otolaryngol ; 115(2): 165-7, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7610796

RESUMEN

A modified version of the Problems Questionnaire was administered to significant others, (SOs) usually spouses, of patients attending audiological rehabilitation clinics. The SOs were asked to list the problems they experienced because of the patient's hearing loss. They were also asked to list the problems the patient was experiencing. In addition the patients were asked to list the problems they experienced and those encountered by their SOs. SO problems concentrated more on difficulties with live speech and psychosocial problems compared with those listed by patients. They also featured more responses indicating dependence. The latter were found particularly among the SOs of male patients whose SOs also emphasised the need to repeat phrases. The SOs of female patients emphasised psychosocial problems.


Asunto(s)
Salud de la Familia , Familia/psicología , Trastornos de la Audición/psicología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Estrés Psicológico/psicología
16.
Audiology ; 34(2): 91-7, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-8561687

RESUMEN

The authors describe the establishment of normative stimulus parameters for the Audioscan, an automated sweep frequency audiometer, for its application in the detection of audiometric notches in carriers of recessive genetic hearing loss. A sweep rate of 30 s/octave over the frequency range 300 to 4000 Hz pulsing at 2.5 pulses/s at -5 dB with a step size of 5 dB were ultimately adopted. The criterion for notches was 15 dB or greater within the frequency range 500-3000 Hz. Adopting this criterion, 14.2% of control subjects had notches. Among parents of children with non-syndromal recessive hearing loss 55% were found to have notches. Notches were found more frequently among mothers and sisters than among fathers and brothers of the patients.


Asunto(s)
Pérdida Auditiva Sensorineural/diagnóstico , Pérdida Auditiva Sensorineural/genética , Adulto , Audiometría , Aberraciones Cromosómicas , Trastornos de los Cromosomas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Factores Sexuales
17.
Virology ; 206(1): 69-75, 1995 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-7831827

RESUMEN

A foot-and-mouth disease virus mutant which is stable at pH 6.4 has been isolated from a virus of serotype A. In contrast to the parent (P) virus, which gave a mixture of large and small plaques in BHK21 cells and in a bovine kidney cell line, the acid-resistant (AR) virus gave small plaques which did not increase markedly in size after 24 hr. The infectivity titer of the acid-resistant virus was about 100-fold lower in suckling mice than in BHK21 cells, whether the inoculation was made intraperitoneally or intracerebrally, whereas the parent virus gave similar titers in both systems. Furthermore, in mice the AR virus reached its end point two to three times more slowly. The diameter of the AR virus was almost 20% less than that of the P virus and it had a more distinct topography, but the two viruses cosedimented in sucrose gradients. However, the buoyant density in CsCl of the AR virus was slightly lower (1.42 compared with 1.43 g/cc) in coruns. The RNAs and capsid proteins of the two viruses gave similar profiles in sucrose gradients and by SDS-PAGE, respectively. However, isoelectric focusing of the capsid proteins revealed considerable differences between the two viruses. Whereas the P virus gave four protein bands, corresponding to VP1-VP4, the AR virus gave one band for VP4, two for VP3, two for VP2, and four for VP1. Sequence analysis of the genes coding for the capsid protein regions of the two viruses showed four changes (one silent), resulting in an Ala-3-->Ser substitution in VP1 and Glu-131-->Lys and Asp-133-->Ser substitutions in VP2.


Asunto(s)
Aphthovirus/genética , Mutación , Animales , Animales Lactantes , Aphthovirus/fisiología , Aphthovirus/ultraestructura , Línea Celular , Cricetinae , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Focalización Isoeléctrica , Ratones , Microscopía Electrónica , Análisis de Secuencia , Proteínas no Estructurales Virales/genética , Replicación Viral
18.
Proc Natl Acad Sci U S A ; 91(18): 8442-6, 1994 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-8078900

RESUMEN

Seven antigenic variants obtained from a single field isolate of foot-and-mouth disease virus, serotype A12, differ only at residues 148 and 153 in the immunodominant loop of viral protein VP1. Synthetic peptides corresponding to the region 141-160 are highly immunogenic. UV circular dichroism shows that (i) in aqueous solution the peptides are nearly identical, but in 100% trifluoroethanol they display helix-forming properties which correlate well with their serological crossreactivities for anti-peptide sera, and (ii) these properties are insensitive to substitutions at position 153, except for proline, but are highly sensitive to substitutions at position 148. This pattern can be explained by the effects of these substitutions on the amphiphilic character and positions of helices postulated in the region 146-156. Molecular models indicate that residues 147, 148, 150, 151, 153-155, and 157 are most likely to interact with residues of the antibody paratopes. The data are consistent with the existence of an inverse gamma-turn around Pro-153, and a beta-turn at the cell-attachment site at residues 145-147.


Asunto(s)
Antígenos Virales/química , Aphthovirus/inmunología , Cápside/inmunología , Secuencia de Aminoácidos , Variación Antigénica , Cápside/química , Proteínas de la Cápside , Dicroismo Circular , Datos de Secuencia Molecular , Péptidos/química , Péptidos/inmunología , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína
19.
Biochim Biophys Acta ; 1202(2): 287-96, 1993 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-7691186

RESUMEN

Outer surface protein A (OspA) is a major antigen of Borrelia burgdorferi, the etiological agent of Lyme disease. A recombinant form of OspA (OspA-257) from B. burgdorferi, strain B31, contains 257 amino acids and a single tryptophan residue at position 216 (Trp-216). Mapping studies indicate that Trp-216 is involved in the epitope for the agglutinating monoclonal antibody 105.5. However, the fluorescence emission maximum of the native protein is 330 nm, indicating that Trp-216 is not solvent-exposed. Primary structure analysis suggests an alpha-helical conformation for residues approx. 204-217, which, if located on the protein surface, would allow Trp-216 to be buried, while leaving hydrophilic residues on the opposite side of the helix exposed. This helix would place Lys-212 within approx. 6 A of Trp-216; the presence of such a positively-charged residue can, in principle, be ascertained from fluorescence quenching studies. Stern-Volmer plots confirm that Trp-216 is indeed buried in the native protein, but is readily accessible to the small polar quencher, acrylamide. Furthermore, the dominant component of the fluorescence emission shows only weak dynamic quenching by the positively-charged quencher, Cs+, while the minor component undergoes static quenching by I-, indicating the proximity of a positively-charged residue. These data are consistent with the existence of an alpha-helix from residues 204-217 in the predicted orientation at the protein surface, hence indicating the structure of the antigenic determinant.


Asunto(s)
Antígenos de Superficie/química , Proteínas de la Membrana Bacteriana Externa/química , Grupo Borrelia Burgdorferi/química , Borrelia burgdorferi , Epítopos/química , Lipoproteínas , Secuencia de Aminoácidos , Vacunas Bacterianas , Lisina/química , Datos de Secuencia Molecular , Estructura Molecular , Espectrometría de Fluorescencia/métodos , Triptófano/química
20.
Br J Pharmacol ; 107(3): 726-31, 1992 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1361872

RESUMEN

1. Evidence is accumulating for multiple sigma (sigma) sites in the mammalian CNS. 2. We have addressed this problem and have examined sigma site - G-protein coupling in guinea-pig and rat brain membranes. 3. Ditolylorthoguanidine (DTG), (+)-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine (3PPP) and dextromethorphan displaced [3H]-DTG (3.4 nM) with low Hill slopes of 0.5, 0.6 and 0.6, respectively in guinea-pig brain membranes. 4. In the presence of 5'-guanylylimidodiphosphate (Gpp(NH)p; 100 microM), the specific binding of [3H]-DTG was reduced by 36.7%, the Hill slope of 3PPP was increased to near unity, the ability of dextromethorphan to displace DTG was virtually abolished and the Hill slope for DTG remained low (0.7), indicating the presence of at least two binding sites. These data indicate that although Gpp(NH)p removes a dextromethorphan high affinity site, two DTG selective sites remain in the presence of Gpp(NH)p. 5. The present study suggests that DTG binds to at least three sites in guinea-pig brain membranes, at least one of which is G-protein linked. 6. In rat brain membranes, DTG displaced itself (3.4 nM) with a Hill slope near 1. 3PPP displacement of [3H]-DTG was comparable with the guinea-pig (Hill slope 0.5) and displaced from more than 1 site. Dextromethorphan did not displace [3H]-DTG at concentrations below 10 microM. 7. The heterogeneity of sigma sites appears to be less in rat than in guinea-pig brain membranes.


Asunto(s)
Química Encefálica/fisiología , Proteínas de Unión al GTP/metabolismo , Receptores Opioides delta/metabolismo , Animales , Unión Competitiva/efectos de los fármacos , Dextrometorfano/farmacología , Dopaminérgicos/farmacología , Guanidinas/farmacología , Cobayas , Técnicas In Vitro , Masculino , Membranas/efectos de los fármacos , Membranas/metabolismo , Piperidinas/farmacología , Ensayo de Unión Radioligante , Ratas , Ratas Wistar
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