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1.
J Laryngol Otol ; 137(5): 541-545, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-35000627

RESUMEN

OBJECTIVE: This study aimed to compare the cost per use of video-rhinolaryngoscopy using reusable and disposable devices in a tertiary referral centre. METHODS: A cost-comparison study was performed that utilised retrospective cost data and prospective utilisation data to compare the total costs of using reusable video-rhinolaryngoscopes versus a single-use alternative. RESULTS: It was estimated that 4776 and 1821 procedures were performed annually with reusable and disposable video-rhinolaryngoscopes, respectively. The cost per use was £66.61 for reusable devices versus £150.00 for disposable devices. The break-even point (i.e. when cost per use was equal, occurred at 1374 procedures per year). Thereafter, it was cheaper to use reusable devices. CONCLUSION: Disposable rhinolaryngoscopes may present a cheaper solution to services with low rates of rhinolaryngoscope utilisation. However, for larger services considering replacement of their reusable rhinolaryngoscopes with disposable units, it is likely that the recurring costs will be prohibitive in the medium to long term.


Asunto(s)
Equipos Desechables , Equipo Reutilizado , Humanos , Estudios Retrospectivos , Estudios Prospectivos , Hospitales de Enseñanza
2.
Ann R Coll Surg Engl ; 103(1): e38-e41, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32985218

RESUMEN

Diplopia is a common presenting complaint with a broad spectrum of differential diagnoses. Causative pathologies may affect the eye, extraocular muscles, neuromuscular junction, cranial nerves and central nervous system. Tumours, inflammatory and autoimmune conditions, vasculopathies and atypical infections are the most common underlying pathologies. Solitary extramedullary plasmacytoma is a rare cause of diplopia. This case emphasises the importance of submucosal biopsies for diagnosis and early involvement of the multidisciplinary team. Moreover, we advocate a low threshold for a second opinion and further immunohistochemistry, particularly when there is diagnostic uncertainty with histological discordance.


Asunto(s)
Enfermedades del Nervio Abducens/diagnóstico , Diplopía/etiología , Plasmacitoma/diagnóstico , Neoplasias de la Base del Cráneo/diagnóstico , Enfermedades del Nervio Abducens/etiología , Anciano , Biopsia , Diagnóstico Diferencial , Humanos , Osteotomía , Plasmacitoma/complicaciones , Plasmacitoma/patología , Base del Cráneo/diagnóstico por imagen , Base del Cráneo/patología , Base del Cráneo/cirugía , Neoplasias de la Base del Cráneo/complicaciones , Neoplasias de la Base del Cráneo/patología , Hueso Esfenoides/diagnóstico por imagen , Hueso Esfenoides/patología , Hueso Esfenoides/cirugía , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
3.
J Laryngol Otol ; 133(11): 1005-1008, 2019 Nov.
Artículo en Francés | MEDLINE | ID: mdl-31587674

RESUMEN

BACKGROUND: Pott's puffy tumour is a rare complication of sinusitis. This osteomyelitis can affect the outer and inner tables of the frontal sinus. The treatment of Pott's puffy tumour combines medical and surgical approaches. Surgical approaches have traditionally been open, but endoscopic techniques have been adopted recently in select cases. The bony defect from debridement can be left alone, or closed with autografts or allografts. OBJECTIVE: To describe a technique for the reconstruction of a large skull vault after the debridement of extensive osteomyelitis of the anterior cranial vault. METHODS: Modified distraction osteogenesis is used in the cranial vault, to induce new bone formation. This is customarily used to lengthen long bones. The advantages of this technique include avoiding autologous grafts or alloplastic cranioplasty in the infected surgical bed, and allowing primary closure. RESULTS: Early post-operative imaging results have been encouraging, with no reported complications. CONCLUSION: Modified distraction osteogenesis is a novel technique in the primary reconstruction of calvarial bone.

4.
Eur Arch Otorhinolaryngol ; 273(4): 827-35, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25567344

RESUMEN

The treatment of post-surgical hypoparathyroidism (following thyroid or parathyroid surgery) is challenging. Presently, this condition is treated with calcium and vitamin D supplements rather than replacing the missing parathyroid hormone. Not only is it challenging to maintain normocalcaemia, but concerns of hypercalciuria and ectopic calcification have also been raised using these supplements. There is an ongoing debate whether recombinant parathyroid hormone (rPTH), which as yet is unlicensed for treating hypoPTH, may offer a more physiological solution. The objective of the study was to assess the effectiveness and safety of rPTH in maintaining normocalcaemia and normocalcuria in hypoparathyroidism. This was a systematic review performed using independently developed search strategies including Medline, Embase, CINAHL, Cochrane, Zetoc, conference proceedings and a manual search until 15 July 2014. Data extraction was undertaken by one reviewer (YR). Studies were synthesised through narrative review with tabulation of results. Of 2,141 studies identified, only eleven studies fitted the inclusion criteria. These studies suggest that rPTH is useful in normalising serum calcium levels. Excretion of urinary calcium levels is reduced with PTH 1-34 but remained unchanged in a number of studies using PTH 1-84. Recombinant PTH is well tolerated. The majority of studies included post-surgical hypoparathyroidism with marked heterogeneity. Further prospective, larger, long-term trials are necessary to evaluate the long-term efficacy and adverse profile of rPTH, including head to head comparisons between PTH 1-34 and PTH 1-84.


Asunto(s)
Hipoparatiroidismo/tratamiento farmacológico , Hormona Paratiroidea/administración & dosificación , Manejo de la Enfermedad , Humanos , Proteínas Recombinantes/administración & dosificación
5.
J Laryngol Otol ; 129(8): 744-51, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26120023

RESUMEN

BACKGROUND: Chronic rhinosinusitis is a common, heterogeneous condition. An effective means of mitigating disease in chronic rhinosinusitis patients remains elusive. A variety of causes have been implicated, with the biofilm theory gaining increasing prominence. OBJECTIVE: This article reviews the literature on the role of biofilms in chronic rhinosinusitis, in terms of pathophysiology and with regard to avenues for future treatment. METHODS: A systematic review of case series was performed using databases with independently developed search strategies, including Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane library, and Zetoc, in addition to conference proceedings and a manual search of literature, with the last search conducted on 18 January 2014. The search terms included the following, used in various combinations to maximise the yield of articles identified: 'biofilms', 'chronic rhinosinusitis', 'DNase', 'extracellular DNA' and 'biofilm dispersal'. RESULTS: The existing evidence lends further support for the role of biofilms (particularly the Staphylococcus aureus phenotype) in more severe, recalcitrant disease and poorer surgical outcomes. CONCLUSION: Multimodality treatment, with a shift in paradigm to incorporate anti-biofilm strategies, is likely to form the mainstay of future recalcitrant chronic rhinosinusitis management.


Asunto(s)
Rinitis/microbiología , Sinusitis/microbiología , Biopelículas , Enfermedad Crónica , Terapia Combinada , Humanos , Rinitis/fisiopatología , Rinitis/terapia , Sinusitis/fisiopatología , Sinusitis/terapia , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/fisiopatología , Infecciones Estafilocócicas/terapia , Staphylococcus aureus/fisiología
6.
J Laryngol Otol ; 127(11): 1103-5, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24169266

RESUMEN

OBJECTIVE: To investigate whether multiple-use Co-phenylcaine Forte® spray was more cost-effective than single-use vials. METHODS: A literature review was conducted to determine the risk of cross-contamination associated with multiple-use topical nasal anaesthetic spray. The costs of multiple-use Co-phenylcaine Forte and single-use co-phenylcaine were compared, and potential savings were calculated. The cost of procuring these drugs from other sources was also examined. RESULTS: Switching to multiple-use Co-phenylcaine Forte spray would lead to at least 40 per cent savings if bought from our local retailer. Potential savings of more than 70 per cent could be made if the drugs were procured from sources other than our local distributor. CONCLUSION: Multiple-use Co-phenylcaine Forte spray is safe to use and more cost-effective than single-use vials. This paper illustrates how money can be saved within the National Health Service through changes in drug procurement. Similar cost savings to those calculated for our department could be made in other ENT departments nationally, depending on their annual consumption of co-phenylcaine.


Asunto(s)
Lidocaína/economía , Descongestionantes Nasales/economía , Fenilefrina/economía , Análisis Costo-Beneficio , Combinación de Medicamentos , Contaminación de Medicamentos/economía , Contaminación de Medicamentos/prevención & control , Sustitución de Medicamentos/economía , Humanos , Lidocaína/administración & dosificación , Descongestionantes Nasales/administración & dosificación , Rociadores Nasales , Fenilefrina/administración & dosificación
7.
J Laryngol Otol ; 125(11): 1141-7, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21899808

RESUMEN

Computed tomography scans serve as a critical 'roadmap' for functional endoscopic sinus surgery. A systematic evaluation of such scans, and an awareness of any anatomical variants that may modify one's surgical approach, allow one to pre-empt complications. This article describes, from a novice's perspective, two methods of evaluating paranasal sinus computed tomography scans: a quick assessment technique; and a step-wise, operative approach covering radiological features relevant to pre- and peri-operative management.


Asunto(s)
Procedimientos Quírurgicos Nasales/métodos , Enfermedades de los Senos Paranasales/cirugía , Senos Paranasales/diagnóstico por imagen , Cuidados Preoperatorios/métodos , Tomografía Computarizada por Rayos X , Endoscopía , Humanos , Procesamiento de Imagen Asistido por Computador , Enfermedades de los Senos Paranasales/diagnóstico por imagen , Senos Paranasales/anatomía & histología , Senos Paranasales/cirugía
8.
J Laryngol Otol ; 125(2): 153-7, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20849670

RESUMEN

OBJECTIVE: To investigate the utilisation of bone-anchored hearing aids and Softband, as well as the effects on quality of life, amongst the paediatric and young adult population of Freeman Hospital, Newcastle Upon Tyne, UK. METHOD: Retrospective, anonymised, cross-sectional survey using the Glasgow Benefit Inventory and Listening Situation Questionnaire (parent version), administered at least three months following the start of bone-anchored hearing aid or Softband use. RESULTS: One hundred and nine patients were included, of whom syndromic children made up a significant proportion (22 of 109). Patients using bone-anchored hearing aids obtained significant educational and social benefit from their aids. The mean Listening Situation Questionnaire difficulty score was 17 (15 patients), which is below the trigger score of 22+ at which further reassessment and rehabilitation is required. 87% (of 15 patients) did not require further intervention. The overall mean GBI score for the 22 patients (syndromic and non-syndromic) was +29. CONCLUSION: The use of bone-anchored hearing aids and Softband results in significant improvements in quality of life for children and young adults with hearing impairment. There is significant under-utilisation of bone-anchored hearing aids in children with skull and congenital abnormalities, and we would advocate bone-anchored hearing aid implantation for these patients.


Asunto(s)
Audífonos/estadística & datos numéricos , Pérdida Auditiva/rehabilitación , Evaluación de Resultado en la Atención de Salud , Satisfacción del Paciente , Adolescente , Adulto , Niño , Preescolar , Síndrome de Down/complicaciones , Métodos Epidemiológicos , Femenino , Estado de Salud , Audífonos/psicología , Pérdida Auditiva/etiología , Humanos , Lactante , Masculino , Disostosis Mandibulofacial/complicaciones , Otitis Media con Derrame/complicaciones , Procedimientos Quirúrgicos Otológicos/métodos , Padres , Calidad de Vida , Reino Unido , Adulto Joven
9.
ISRN Otolaryngol ; 2011: 540643, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-23724254

RESUMEN

Neurogenic tumours of the larynx, particularly schwannomas are rare. We report a case report of a schwannoma in a 30-year-old woman which was excised endoscopically. The aim of this paper is to highlight this rare condition and management options to the otolaryngological community.

10.
Bioanalysis ; 2(8): 1515-22, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21083351

RESUMEN

BACKGROUND: A clinical investigation was performed into the practicalities of the collection of blood samples for the determination of drug exposures on filter paper, known as dried blood spot (DBS) sampling using a two-period, single-dose, open-label trial conducted in 11 healthy volunteers who received a single oral dose of paracetamol. Questionnaires relating to the blood sampling and spotting process and tolerability were completed by staff and volunteers. Paracetamol concentrations in DBS samples obtained by venous cannula (DBS-Can) were compared against those from fingerprick (DBS-FP) and fresh whole blood obtained from a cannula (WB-Can). RESULTS: The questionnaires demonstrated that FP and blood spotting was easy to perform and well tolerated and compared favorably with cannula sampling. Paracetamol concentrations in DBS-Can were greater than those in WB-Can (positive bias) except below 8000 ng/ml when both were interchangeable. When comparing DBS-FP to DBS-Can, both the bias and variability differed significantly across the five sampling time points. CONCLUSION: The study has shown that the DBS technique is practical in the context of a clinical trial. Interchangeability of drug concentrations between blood sampling site and mode of blood collection has to be checked and taken into account when designing pharmacokinetic studies for other compounds.


Asunto(s)
Acetaminofén/sangre , Análisis Químico de la Sangre/métodos , Recolección de Muestras de Sangre/métodos , Acetaminofén/administración & dosificación , Acetaminofén/farmacocinética , Desecación , Relación Dosis-Respuesta a Droga , Femenino , Congelación , Humanos , Masculino , Encuestas y Cuestionarios , Factores de Tiempo , Agua/química
11.
J Laryngol Otol ; 124(11): 1146-52, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20546647

RESUMEN

BACKGROUND: An understanding of the management of chronic facial palsy is vital for otolaryngologists, due to its common presentation to ENT surgeons. There is currently a lack of consensus on the optimum management of this condition. This article reviews the existing literature and offers a perspective on current management, as well as an insight into future treatments. METHODS: A literature search was performed, using the Medline, Embase and Cochrane databases from 1966 to the present, using the keywords listed below. Articles were reviewed. Selection was limited to English language articles on human subjects. RESULTS AND CONCLUSION: A tailored, multidisciplinary approach using combinatorial therapy should be used for reanimation of the face following facial palsy. Advances in surgical and non-surgical techniques, and the exchange of information from centres of excellence via global databases, will enable objective appraisal of results and the development of an evidence-based approach to facial reanimation.


Asunto(s)
Parálisis Facial/terapia , Adulto , Terapia Combinada/métodos , Técnicas Cosméticas , Descompresión Quirúrgica , Medicina Basada en la Evidencia , Asimetría Facial/etiología , Asimetría Facial/cirugía , Nervio Facial/cirugía , Parálisis Facial/diagnóstico , Parálisis Facial/etiología , Trasplante Facial/tendencias , Predicción , Humanos , Recién Nacido , Músculo Esquelético/trasplante , Transferencia de Nervios/métodos , Procedimientos de Cirugía Plástica/métodos , Procedimientos de Cirugía Plástica/tendencias , Recuperación de la Función
12.
Clin Otolaryngol ; 32(6): 484-8, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18076440

RESUMEN

OBJECTIVES: Comorbidity has been shown to be a determinant in treatment selection and survival in squamous cell cancer of the head and neck at various subsites. The objective of this study is to analyse the effect of comorbidity burden on outcome of nasopharyngeal cancer using the Adult Comorbidity Evaluation-27 (ACE-27) instrument. DESIGN: Retrospective analysis. SETTING: Tertiary care centres. PARTICIPANTS: This study included 59 patients diagnosed with nasopharyngeal carcinoma between 1989-2003 in the North-East of England. Exclusion criteria included non-squamous neoplasms of the nasopharynx. Comorbidity was assessed retrospectively from the notes using standard validated techniques described earlier. Tumour, treatment and survival data were obtained from prospective databases. Data was analysed using SPSS for Windows. MAIN OUTCOME MEASURES: Comorbidity and outcome of treatment. RESULTS: Comorbid burden was evident in 44% of patients, with moderate or severe comorbidity in 19%. The cardiovascular system was the most commonly affected system (27%). Cox's proportional hazard model showed age and stage of tumour to have an impact on disease specific survival. Comorbidity was not seen to predict the outcome independent of other factors. The sample size of this study is powered to detect only medium to large effects. We estimate that 614 subjects will be needed to detect a correlation coefficient of 0.1 with 80% power, assuming a type 1 error rate of 5%. CONCLUSION: This study shows for the first time that the comorbidity burden seen in nasopharyngeal cancer does not affect prognosis independent of the TNM staging.


Asunto(s)
Neoplasias Nasofaríngeas/epidemiología , Neoplasias Nasofaríngeas/terapia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Comorbilidad , Inglaterra/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento
13.
J Laryngol Otol ; 121(8): 713-20, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17359559

RESUMEN

BACKGROUND: The diagnosis and management of olfactory disorders is an often neglected topic in otolaryngology. This article evaluates current clinical practice within the United Kingdom, and provides a literature-based review of the diagnosis, management and prognosis of olfactory pathology. DESIGN: A questionnaire was sent to consultant and associate specialist members of the British Association of Otolaryngologists and Head and Neck Surgeons. The responses were documented to gain an impression of how olfactory disorders are managed in the United Kingdom. The literature relating to olfactory dysfunction was then evaluated and the findings summarised. CONCLUSIONS: Management of olfactory pathology varies across the United Kingdom. The literature suggests that chemosensory testing is optimal and that both forced-choice and threshold testing should be applied if objective evaluation is required. Imaging can be of value but the appropriate technique should be used. Olfactory function can recover following head injury, viral infection and chronic sinonasal disease, although varying degrees of dysfunction are likely to persist. There is a role for the use of corticosteroids, particularly when administered systemically. More research is needed to establish the appropriate dose and length of treatment.


Asunto(s)
Trastornos del Olfato , Traumatismos Craneocerebrales/complicaciones , Medicina Basada en la Evidencia , Glucocorticoides/uso terapéutico , Encuestas de Atención de la Salud , Humanos , Trastornos del Olfato/diagnóstico , Trastornos del Olfato/etiología , Trastornos del Olfato/terapia , Infecciones del Sistema Respiratorio/complicaciones , Rinitis/complicaciones , Sinusitis/complicaciones , Tomografía Computarizada por Rayos X , Reino Unido
14.
J Laryngol Otol ; 121(6): 521-5, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17201990

RESUMEN

Retraction pockets can lead to hearing loss and cholesteatoma. Distinguishing stable from progressive disease is challenging to any otologist. The management of retraction pockets is a contentious issue with present treatment options often plagued with recurrence. The purpose of this article is to summarize recent developments in the aetiology of retraction pockets of the pars tensa, its diagnostic and management problems and to define possible future therapeutic options.


Asunto(s)
Enfermedades del Oído/patología , Membrana Timpánica/patología , Adulto , Niño , Preescolar , Colesteatoma del Oído Medio/fisiopatología , Colesteatoma del Oído Medio/prevención & control , Enfermedades del Oído/cirugía , Trompa Auditiva/patología , Trompa Auditiva/fisiopatología , Femenino , Humanos , Masculino , Otitis Media/etiología , Otitis Media/fisiopatología , Recurrencia , Índice de Severidad de la Enfermedad , Membrana Timpánica/cirugía
16.
Acta Neurochir (Wien) ; 147(8): 839-45, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15959858

RESUMEN

BACKGROUND: Carotid Endarterectomy can be performed under local, regional or general anaesthesia. One of the most important effects of the type of anaesthetic used is on the systemic blood pressure. Although variations in blood pressure during and following carotid endarterectomy have been studied previously, the effects of awake carotid endarterectomy under local anaesthesia on blood pressure and its comparison with similar procedures under similar types of anaesthesia have not. METHODS: Peri-operative blood pressure measurements were collected from the records of 25 consecutive patients for each of the following five procedures; Carotid Endarterectomy under general anaesthesia (CEAGA), Anterior Cervical Discectomy and Fusion under general anaesthesia (ACDF), Cerebral Angiography under local anaesthesia (ANG), Carotid Endarterectomy patients under local anaesthesia who were symptomatic (CEALAS) and Carotid Endarterectomy patients under local anaesthesia who were asymptomatic (CEALAA). The recordings were then analysed to find out if there were any clinically significant variations in peri-operative blood pressure. FINDINGS: There is a significant and consistent difference when the pre-operative value was compared with the 4 hour and 24 hour post-operative recordings between the local and general anaesthetic groups for carotid endarterectomy. Carotid endarterectomy reduces the systolic and diastolic blood pressures post-operatively when performed under local anaesthesia and only the diastolic pressure was reduced when performed under general anaesthesia. CONCLUSION: The study provides evidence about the effect of carotid endarterectomy on the systemic blood pressure and its variations when performed under different types of anaesthesia. There is significant post-operative reduction in both the systolic and diastolic blood pressure values and the intraoperative fluctuation is minimal when local anaesthesia is used. Further studies are required to find out how this affects the long-term blood pressure and clinical outcome of the patient.


Asunto(s)
Anestesia General , Anestesia Local , Presión Sanguínea/fisiología , Estenosis Carotídea/fisiopatología , Estenosis Carotídea/cirugía , Endarterectomía Carotidea , Estenosis Carotídea/complicaciones , Angiografía Cerebral , Vértebras Cervicales , Discectomía , Humanos , Estudios Retrospectivos , Fusión Vertebral
17.
Cell Res ; 14(5): 373-8, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15538969

RESUMEN

Mitsugumin 29 (MG29) is a transmembrane protein that is normally found in the triad junction of skeletal muscle. Our previous studies have shown that targeted deletion of mg29 from the skeletal muscle resulted in abnormality of the triad junction structure, and also increased susceptibility to muscle fatigue. To elucidate the basis of these effects, we investigated the properties of Ca2+-uptake and -release in toxin-skinned Extensor Digitorium Longus (EDL) muscle fibers from control and mg29 knockout mice. Compared with the control muscle, submaximal Ca2+-uptake into the sarcoplasmic reticulum (SR) was slower and the storage of Ca2+ inside the SR was less in the mutant muscle, due to increased leakage process of Ca2+ movement across the SR. The leakage pathway is associated with the increased sensitivity of Ca2+/caffeine -induced Ca2+ release to myoplasmic Ca2+. Therefore, the increased fatigability of mutant EDL muscles can result from a combination of a slowing of Ca2+ uptake, modification of Ca2+-induced Ca2+ release (CICR), and a reduction in total SR Ca2+ content.


Asunto(s)
Calcio/metabolismo , Calcio/farmacocinética , Homeostasis/fisiología , Fatiga Muscular/fisiología , Proteínas Musculares/genética , Sinaptofisina/análogos & derivados , Sinaptofisina/genética , Animales , Cafeína/farmacología , Homeostasis/efectos de los fármacos , Ionomicina/farmacología , Ratones , Ratones Noqueados , Fatiga Muscular/efectos de los fármacos , Fatiga Muscular/genética , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/fisiología , Retículo Sarcoplasmático/efectos de los fármacos , Retículo Sarcoplasmático/fisiología , Factores de Tiempo
18.
J Biol Chem ; 279(19): 19387-90, 2004 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-15039443

RESUMEN

Perturbation of intracellular Ca2+ homeostasis has been shown to regulate the process of cell proliferation and apoptosis. Our previous studies show that mitsugumin 29 (MG29), a synaptophysin-related protein localized in the triad junction of skeletal muscle, serves an essential role in muscle Ca2+ signaling by regulating the process of store-operated Ca2+ entry. Here we report a functional interaction between MG29 and the ryanodine receptor (RyR)/Ca2+ release channel. The purified MG29 protein enhances activity of the RyR/Ca2+ release channel incorporated into the lipid bilayer membrane. Co-expression of MG29 and RyR in Chinese hamster ovary cells leads to apoptotic cell death resulting from depletion of intracellular Ca2+ stores, despite neither protein expression alone exhibits any significant effect on cell viability. In transient expression studies, the presence of RyR in the endoplasmic reticulum leads to retention of MG29 from the plasma membrane into the intracellular organelles. This functional interaction between MG29 and RyR could have important implications in the Ca2+ signaling processes of muscle cells. Our data also show that perturbation of intracellular Ca2+ homeostasis can serve as a key signal in the initiation of apoptosis.


Asunto(s)
Apoptosis , Calcio/metabolismo , Proteínas Musculares/biosíntesis , Canal Liberador de Calcio Receptor de Rianodina/biosíntesis , Sinaptofisina/biosíntesis , Adenosina Trifosfato/química , Animales , Western Blotting , Células CHO , División Celular , Membrana Celular/metabolismo , Clonación Molecular , Cricetinae , ADN/química , Electrofisiología , Retículo Endoplásmico/metabolismo , Proteínas Fluorescentes Verdes , Proteínas Luminiscentes/metabolismo , Microscopía Confocal , Proteínas Musculares/fisiología , Músculo Esquelético/metabolismo , Mutagénesis Sitio-Dirigida , Unión Proteica , Conejos , Canal Liberador de Calcio Receptor de Rianodina/fisiología , Transducción de Señal , Sinaptofisina/análogos & derivados , Sinaptofisina/fisiología , Transfección
19.
Nat Cell Biol ; 4(5): 379-83, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-11988740

RESUMEN

The store-operated calcium channel (SOC) located in the plasma membrane (PM) mediates capacitative entry of extracellular calcium after depletion of intracellular calcium stores in the endoplasmic or sarcoplasmic reticulum (ER/SR). An intimate interaction between the PM and the ER/SR is essential for the operation of this calcium signalling pathway. Mitsugumin 29 (MG29) is a synaptophysin-family-related protein located in the junction between the PM and SR of skeletal muscle. Here, we identify SOC in skeletal muscle and characterise its regulation by MG29 and the ryanodine receptor (RyR) located in the SR. Targeted deletion of mg29 alters the junctional membrane structure, causes severe dysfunction of SOC and SR calcium homeostasis and increases the susceptibility of muscle to fatigue stimulation. Severe dysfunction of SOC is also identified in muscle cells lacking both type 1 and type 3 RyRs, indicating that SOC activation requires an intact interaction between the PM and the SR, and is linked to conformational changes of RyRs. Whereas defective SOC seems to be inconsequential to short-term excitation-contraction coupling, the slow cumulative calcium entry through SOC is crucial for long-term calcium homeostasis, such that reduced SOC activity exaggerates muscle fatigue under conditions of intensive exercise.


Asunto(s)
Canales de Calcio/metabolismo , Señalización del Calcio/fisiología , Proteínas Musculares , Músculo Esquelético/fisiología , Sinaptofisina/análogos & derivados , Sinaptofisina/metabolismo , Animales , Calcio/metabolismo , Canales de Calcio/genética , Membrana Celular/metabolismo , Células Cultivadas , Homeostasis , Ratones , Fatiga Muscular , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/ultraestructura , Canal Liberador de Calcio Receptor de Rianodina/genética , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo , Sinaptofisina/genética
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