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3.
Hong Kong Med J ; 17(4): 332-4, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21813905

RESUMEN

Small-cell carcinomas of lung origin have been well characterised for their clinico-histopathological features. However, extrapulmonary small-cell carcinomas are rare, and in particular, they are extremely rare at the ampullary region. We report herein a case of small-cell carcinoma of ampulla of Vater and review its clinical, histological, and immunohistochemical features.


Asunto(s)
Ampolla Hepatopancreática , Carcinoma de Células Pequeñas/complicaciones , Neoplasias del Conducto Colédoco/complicaciones , Ictericia Obstructiva/etiología , Humanos , Masculino , Persona de Mediana Edad
4.
Hong Kong Med J ; 17(1): 11-9, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21282821

RESUMEN

OBJECTIVES: To determine the development rate of hepatocellular carcinoma and survival of patients diagnosed to have regenerative, and low-grade and high-grade dysplastic liver nodules. DESIGN: Retrospective descriptive study. SETTING: Acute public hospital, Hong Kong. PATIENTS: Patients with non-malignant liver nodules confirmed by imaging-guided liver biopsy between January 1997 and December 2008. MAIN OUTCOME MEASURES: Rates of hepatocellular carcinoma development and survival. RESULTS: A total of 147 patients with non-malignant liver nodules were followed up over a median duration of 29 months. The initial histological diagnosis included regenerative nodules (n=74), low-grade dysplastic nodules (n=34), and high-grade dysplastic nodules (n=39). The respective cumulative hepatocellular carcinoma development rate during the first, second, third, and fourth year were 3%, 5%, 9% and 12% for simple regenerative nodules, 29%, 35%, 38% and 44% for low-grade dysplastic nodules, and 38%, 41%, 51% and 51% for high-grade dysplastic nodules. The hepatocellular carcinoma development rate was highest in those with high-grade dysplastic nodules. Multivariate analysis showed that histological dysplastic changes were associated with increased alpha-fetoprotein levels and advanced age, which were both independent predictors of hepatocellular carcinoma development. Histological dysplastic changes, male sex, advanced age, prolonged prothrombin time, and ultrasound appearances were independent predictors of mortality. CONCLUSION: The presence of dysplastic change in liver nodules increased the risk of hepatocellular carcinoma development and death.


Asunto(s)
Carcinoma Hepatocelular/etiología , Neoplasias Hepáticas/etiología , Regeneración Hepática , Hígado/patología , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Femenino , Humanos , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Retrospectivos
5.
Hong Kong Med J ; 16(5): 362-6, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20890000

RESUMEN

OBJECTIVE: To describe the epidemiology, clinical features, and treatment outcome of achalasia in Chinese patients. DESIGN: Retrospective study. SETTING: Major regional hospital, Hong Kong. PATIENTS: Clinical records of patients with the diagnosis of achalasia from July 1997 to June 2007 were reviewed. RESULTS: Thirty-two patients were diagnosed with achalasia during the study period. The mean age at diagnosis was 50 years (standard deviation, 20 years). The female-to-male ratio was 1.3:1. The main presenting symptoms were dysphagia (78%) and vomiting (50%). Nine laparoscopic and two open Heller's operations had been performed and 16 patients had undergone endoscopic dilatations. Four patients had botulinum toxin injection and four were taking calcium channel blocker (nifedipine) medications. Botulinum toxin injection and medical therapy had poor short- and long-term responses. Laparoscopic myotomy and pneumatic dilatation had comparable good short- and long-term responses. CONCLUSION: Achalasia affected all age-groups but there was a peak at middle age. Pneumatic dilatation and Heller's myotomy (open or laparoscopic approach) appeared able to maintain longer symptom responses than medical therapy and botulinum toxin injection.


Asunto(s)
Trastornos de Deglución/etiología , Acalasia del Esófago/terapia , Vómitos/etiología , Adulto , Distribución por Edad , Anciano , Toxinas Botulínicas/uso terapéutico , Cateterismo/métodos , Acalasia del Esófago/epidemiología , Acalasia del Esófago/fisiopatología , Femenino , Estudios de Seguimiento , Hong Kong/epidemiología , Humanos , Laparoscopía/métodos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
6.
J Nutr Health Aging ; 13(2): 96-101, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19214336

RESUMEN

OBJECTIVES: To determine the cut off score of the CNS in predicting 12 months mortality. DESIGN: Data was collected and followed up from a previous study among elderly subjects (n = 515) living in community institutional setting. The risk of malnutrition and 12 months mortality was ranked by the CNS and compared with that by SGA. Reliability was assessed by the sensitivity and specificity of the prediction with SGA as well as BMI alone. Sensitivity and specificity was calculated to determine validity as well as using positive and negative predictive values in predicting mortality at 12 months. RESULTS: All three tools (BMI, SGA, CNS) demonstrated significant difference of higher mortality rate (P < .001) in the malnourished group. CNS at score < or = 21 showed comparable results to SGA tool and BMI at classifying malnutrition. And using cut off score > or = 22 also show significant results with SGA in classifying patients with normal nutrition. CNS score at > or = 22 sensitivity was 60.9% and specificity was 72.9% with a Negative Predictive value of 92.3% and a Positive Predictive value of 25.8%. CONCLUSION: CNS tool at cut off > or = 22 is just as good as using BMI or SGA in identifying those who have a normal nutritional status. This is useful in particular, when biochemical or anthropometric data is not available. This further validates the use of > or = 22 as the best cut off point with the CNS tool and just as good at predicting of mortality when compared with SGA and BMI assessments.


Asunto(s)
Índice de Masa Corporal , Evaluación Geriátrica/métodos , Desnutrición/diagnóstico , Evaluación Nutricional , Estado Nutricional , Anciano , Pueblo Asiatico/etnología , Femenino , Hogares para Ancianos , Hong Kong/epidemiología , Humanos , Institucionalización , Masculino , Desnutrición/etnología , Desnutrición/mortalidad , Casas de Salud , Estado Nutricional/etnología , Valores de Referencia , Reproducibilidad de los Resultados , Factores de Riesgo , Sensibilidad y Especificidad , Encuestas y Cuestionarios
7.
Hong Kong Med J ; 15(5): 339-45, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19801690

RESUMEN

OBJECTIVE: To evaluate survival and prognostic factors in patients with advanced hepatocellular carcinoma treated by transarterial chemoembolisation in a real-life clinical practice setting. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Patients with inoperable hepatocellular carcinoma diagnosed from January 1998 to December 2003 who received transarterial chemoembolisation. RESULTS: A total of 74 patients were identified, and had a median survival of 214 days. The cumulative survival rates at 1, 2, and 3 years were 28%, 12%, and 7%, respectively. By multivariate analysis, superselective cannulation performed in transarterial chemoembolisation (hazard ratio=0.47; 95% confidence interval, 0.23-0.95; P=0.034), embolisation with gelfoam (0.30; 0.11-0.80; P=0.017), and treatment intervals of more than 45 days (0.33; 0.15-0.72; P=0.006) were independent predictors of good survival. Child-Pugh grade B cirrhosis (hazard ratio=5.62; 95% confidence interval, 2.11-14.97; P=0.001), and high pre-treatment serum alpha-fetoprotein level (2.93; 1.50-5.73; P=0.002) were independent predictors of poor survival. CONCLUSIONS: In real-life clinical practice, survival of patients with inoperable hepatocellular carcinoma remains grave despite treatment. Patients with Child-Pugh grade A cirrhosis or with low pretreatment alpha-fetoprotein level are more suitable for this form of treatment. The procedure should be performed with superselective cannulation and embolisation with gelfoam.


Asunto(s)
Carcinoma Hepatocelular/terapia , Quimioembolización Terapéutica/métodos , Esponja de Gelatina Absorbible/administración & dosificación , Neoplasias Hepáticas/terapia , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Femenino , Hong Kong , Humanos , Cirrosis Hepática/patología , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Análisis Multivariante , Pronóstico , Estudios Retrospectivos , Análisis de Supervivencia , Tasa de Supervivencia , Resultado del Tratamiento , alfa-Fetoproteínas/metabolismo
8.
ACS Med Chem Lett ; 9(2): 73-77, 2018 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30555625

RESUMEN

Herein, we describe the synthesis and structure-activity relationships of cyclic peptides designed to target heat shock protein 90 (Hsp90). Generating 19 compounds and evaluating their binding affinity reveals that increasing electrostatic interactions allows the compounds to bind more effectively with Hsp90 compared to the lead structure. Exchanging specific residues for lysine improves binding affinity for Hsp90, indicating some residues are not critical for interacting with the target, whereas others are essential. Replacing l- for d-amino acids produced compounds with decreased binding affinity compared to the parent structure, confirming the importance of conformation and identifying key residues most important for binding. Thus, a specific conformation and electrostatic interactions are required in order for these inhibitors to bind to Hsp90.

9.
Neuroscience ; 146(2): 594-603, 2007 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-17368953

RESUMEN

Tight regulation of gene transcription is critical in muscle development as well as during the formation and maintenance of the neuromuscular junction (NMJ). We previously demonstrated that the transcription of G protein beta1 (Gbeta1) is enhanced by treatment of cultured myotubes with neuregulin (NRG), a trophic factor that plays an important role in neural development. In the current study, we report that the transcript levels of Gbeta1 and Gbeta2 subunits in skeletal muscle are up-regulated following sciatic nerve injury or blockade of nerve activity. These observations prompted us to explore the possibility that G protein subunits regulate NRG-mediated signaling and gene transcription. We showed that overexpression of Gbeta1 or Gbeta2 in COS7 cells attenuates NRG-induced extracellular signal-regulated kinase (ERK) 1/2 activation, whereas suppression of Gbeta2 expression in C2C12 myotubes enhances NRG-mediated ERK1/2 activation and c-fos transcription. These results suggest that expression of Gbeta protein negatively regulates NRG-stimulated gene transcription in cultured myotubes. Taken together, our observations provide evidence that specific heterotrimeric G proteins regulate NRG-mediated signaling and gene transcription during rat muscle development.


Asunto(s)
Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Células Musculares/metabolismo , Músculo Esquelético/citología , Neurregulinas/fisiología , Neuropatía Ciática/fisiopatología , Transducción de Señal/fisiología , Anestésicos Locales/farmacología , Animales , Animales Recién Nacidos , Células Cultivadas , Chlorocebus aethiops , Embrión de Mamíferos , Subunidades beta de la Proteína de Unión al GTP , Regulación del Desarrollo de la Expresión Génica/fisiología , Células Musculares/efectos de los fármacos , Desnervación Muscular/métodos , Neurregulinas/farmacología , Ratas , Transducción de Señal/efectos de los fármacos , Tetrodotoxina/farmacología , Factores de Tiempo , Transfección/métodos
10.
Hong Kong Med J ; 13(6): 436-41, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18057431

RESUMEN

OBJECTIVE: To study the descriptive epidemiology and clinical profile of patients with Crohn's disease. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Patients with Crohn's disease diagnosed between January 1991 and December 2006 inclusive. RESULTS: Over the period studied, 27 Chinese patients were diagnosed with Crohn's disease in our hospital. Our hospital-based incidence and prevalence rate had increased more than 2- and 5-fold, respectively over that period. The mean age at diagnosis was 26 years and median duration of disease was 81 months. Most patients had ileocolonic disease (67%) followed by Crohn's colitis (22%) and ileal disease (11%); more patients had non-stricturing and non-penetrating disease (63%) than stricturing (15%) or penetrating disease (22%). Peri-anal disease occurred in 37% of our patients. At diagnosis, many of the patients (41%) had mild-moderate disease, but 30% each had moderate-severe and severe-fulminant disease. At the time of this study, 85% of the patients were in disease remission with medical treatment. However, 48% had undergone surgery for diagnosis or complications. No patient had developed colorectal cancer or died. CONCLUSIONS: The incidence and prevalence of Crohn's disease are increasing in the Chinese population. It usually affects young persons with a substantial proportion of patients presented with severe-fulminant disease. More epidemiological and clinical studies are needed for this emerging disease in Asian regions.


Asunto(s)
Enfermedad de Crohn/epidemiología , Adolescente , Adulto , Niño , Enfermedad de Crohn/terapia , Femenino , Hong Kong/epidemiología , Hospitales , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Fenotipo , Prevalencia , Estudios Retrospectivos , Resultado del Tratamiento
11.
Health Serv Res ; 50(2): 614-24, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25100068

RESUMEN

OBJECTIVE: To demonstrate the importance of diagnostic aggregation when assessing hospitals. DATA SOURCES: Patient data from the Victorian Admitted Episodes Database (VAED), 1999/2000 to 2004/2005. Financial statements from public hospitals, 2002/2003 to 2004/2005. STUDY DESIGN: Risk-adjusted quality computed for each hospital using two aggregation levels. Each is then used to estimate the relationship between hospital efficiency and quality using two-stage DEA/Tobit model by Wilson and Simar (2006). DATA COLLECTION: Selected variables from the VAED were obtained from the Department of Health in Victoria, then linked anonymously with financial statements. PRINCIPAL FINDINGS: Hospital quality and, in some cases, its relationship with efficiency differs depending on aggregations. CONCLUSIONS: Patient risk adjustment should be conducted using more than one aggregation level whenever possible.


Asunto(s)
Eficiencia Organizacional , Administración Hospitalaria/estadística & datos numéricos , Calidad de la Atención de Salud/estadística & datos numéricos , Ajuste de Riesgo/estadística & datos numéricos , Humanos , Revisión de Utilización de Seguros , Ajuste de Riesgo/métodos , Victoria
12.
Obes Rev ; 16(11): 1001-15, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26252230

RESUMEN

Body mass index (BMI) and mortality in old adults from the general population have been related in a U-shaped or J-shaped curve. However, limited information is available for elderly nursing home populations, particularly about specific cause of death. A systematic PubMed/EMBASE/CINAHL/SCOPUS search until 31 May 2014 without language restrictions was conducted. As no published study reported mortality in standard BMI groups (<18.5, 18.5-24.9, 25-29.9, ≥30 kg/m(2)), the most adjusted hazard ratios (HRs) according to a pre-defined list of covariates were obtained from authors and pooled by random-effect model across each BMI category. Out of 342 hits, 20 studies including 19,538 older nursing home residents with 5,223 deaths during a median of 2 years of follow-up were meta-analysed. Compared with normal weight, all-cause mortality HRs were 1.41 (95% CI = 1.26-1.58) for underweight, 0.85 (95% CI = 0.73-0.99) for overweight and 0.74 (95% CI = 0.57-0.96) for obesity. Underweight was a risk factor for higher mortality caused by infections (HR = 1.65 [95% CI = 1.13-2.40]). RR results corroborated primary HR results, with additionally lower infection-related mortality in overweight and obese than in normal-weight individuals. Like in the general population, underweight is a risk factor for mortality in old nursing home residents. However, uniquely, not only overweight but also obesity is protective, which has relevant nutritional goal implications in this population/setting.


Asunto(s)
Índice de Masa Corporal , Anciano Frágil/estadística & datos numéricos , Hogares para Ancianos/estadística & datos numéricos , Casas de Salud/estadística & datos numéricos , Sobrepeso/mortalidad , Delgadez/mortalidad , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Fenómenos Fisiológicos de la Nutrición , Factores de Riesgo
13.
Chest ; 120(6): 1877-82, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11742916

RESUMEN

OBJECTIVE: This study demonstrates the value of Mycobacterium tuberculosis fingerprinting used in conjunction with traditional epidemiologic methods to identify smoldering outbreaks of tuberculosis in endemic areas where background rates of tuberculosis are high. METHODS: IS6110 DNA fingerprinting was performed on isolates of M tuberculosis from verified cases of tuberculosis in Alabama from 1994 to 1998. A statewide database groups isolates into "clusters" and tracks them cumulatively over time. A large cluster was identified and was secondarily investigated using traditional epidemiologic methods. RESULTS: Twenty-five isolates were found to be identical by fingerprinting analysis. Patients were living within 10 counties across the state, and 12 cases were localized to a single county. This represented an ongoing, statewide tuberculosis outbreak previously unrecognized by local and state health officials. Secondary investigation of the cases revealed the primary sites of transmission to be a correctional facility and two homeless shelters. CONCLUSIONS: Population surveillance using M tuberculosis fingerprinting was successfully utilized to detect a significant and smoldering tuberculosis outbreak. Measures are currently in place to identify and prevent further transmission in the involved locations.


Asunto(s)
Dermatoglifia del ADN , Brotes de Enfermedades , Mycobacterium tuberculosis/genética , Vigilancia de la Población , Población Rural , Tuberculosis/epidemiología , Adulto , Alabama/epidemiología , Trazado de Contacto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo de Longitud del Fragmento de Restricción , Valor Predictivo de las Pruebas , Factores de Riesgo , Tuberculosis/diagnóstico , Tuberculosis/transmisión
15.
Int J Tuberc Lung Dis ; 2(8): 655-62, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9712280

RESUMEN

SETTING: Alabama State Tuberculosis Control Program, USA. OBJECTIVE: To combine molecular screening data with routine information to assess transmission of Mycobacterium tuberculosis and improve control efforts. DESIGN: Since January 1994, samples from tuberculosis cases statewide have been systematically analyzed by IS6110 restriction fragment length polymorphism (RFLP). All cases during 1994-1995 with a predominate RFLP pattern were evaluated and risk factors assessed. pTBN12 was used to evaluate a large cluster in the Birmingham-Jefferson County (BJC) area. RESULTS: Statewide, a common two-band pattern was found, named JH2 (99/566, 17.5%). The most important risk associated with this pattern was homelessness (odds ratio, 8.9; P < 0.001). In the BJC area, the homeless accounted for 29% (51/175) of new cases diagnosed during the study period. For the BJC homeless, there were 13 unique RFLP patterns, and JH2 was predominant (29/33, 88%) among three clusters. Secondary analysis of the homeless JH2 cluster revealed a large group that included 19 of 24 (79%) isolates analyzed. Compared with the BJC non homeless (n = 124), the homeless were younger (P < 0.001), of male gender (P < 0.001), black race (P = 0.002), and were heavy alcohol (P < 0.001) and non-injection drug (P = 0.001) users. CONCLUSIONS: By screening tuberculosis cases statewide, a common two-band RFLP pattern was identified. Its predominance is explained by an ongoing tuberculosis epidemic among Birmingham's homeless population, highlighting RFLP as a tool for population surveillance. The pattern differences observed by pTBN12 typing clearly demonstrate that the isolates might be related but are not clonal.


Asunto(s)
Mycobacterium tuberculosis/genética , Polimorfismo de Longitud del Fragmento de Restricción , Vigilancia de la Población , Tuberculosis/epidemiología , Adulto , Alabama/epidemiología , Dermatoglifia del ADN , Femenino , Personas con Mala Vivienda , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Tuberculosis/transmisión
16.
Int J Tuberc Lung Dis ; 3(7): 613-9, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10423224

RESUMEN

SETTING: Two homeless shelters in Birmingham, Alabama. OBJECTIVE: To interrupt tuberculosis transmission and evaluate the utility of spot sputum screening. DESIGN: Two shelters participated in the study between May 1996 and February 1997. A spot sputum specimen was collected on a given evening from each overnight client. Information was obtained regarding symptoms and tuberculin skin test (TST) status. There were four screenings during two rounds, with TST in round one only. RESULTS: Of 127 persons involved in the study, 120 (95%) provided specimens, and four tuberculosis cases were identified (4/127, 3.1%). Symptoms were infrequently reported. RFLP analysis (IS6110) confirmed a two-band cluster in three of the four cases; another matching two-band strain was found in a drug rehabilitation client staying in one shelter. Secondary RFLP typing (pTBN12) confirmed the homeless cluster. Costs were $1311 per case identified. Among 92 clients with a prior TST, 40% reported a positive result (37/92). Of 21 PPD tests read, 11 were > or =10 mm (52%). CONCLUSION: Spot sputum screening is effective in identifying unsuspected tuberculosis cases in shelters. It has acceptable costs, is logistically simple and efficient. Symptom screening was not useful in this general homeless population. RFLP analysis showed cloning of the two-band strain. Given the evidence for ongoing transmission, sputum screening should be considered in shelter settings.


Asunto(s)
Personas con Mala Vivienda/estadística & datos numéricos , Tamizaje Masivo/métodos , Mycobacterium tuberculosis/aislamiento & purificación , Esputo/microbiología , Tuberculosis/diagnóstico , Adulto , Alabama , Costos y Análisis de Costo , Estudios de Evaluación como Asunto , Femenino , Vivienda/estadística & datos numéricos , Humanos , Masculino , Tamizaje Masivo/economía , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Prueba de Tuberculina , Tuberculosis/prevención & control
18.
Dis Model Mech ; 7(12): 1351-63, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25288684

RESUMEN

Mutations in LRRK2 cause a dominantly inherited form of Parkinson's disease (PD) and are the most common known genetic determinant of PD. Inhibitor-based therapies targeting LRRK2 have emerged as a key therapeutic strategy in PD; thus, understanding the consequences of inhibiting the normal cellular functions of this protein is vital. Despite much interest, the physiological functions of LRRK2 remain unclear. Several recent studies have linked the toxicity caused by overexpression of pathogenic mutant forms of LRRK2 to defects in the endolysosomal and autophagy pathways, raising the question of whether endogenous LRRK2 might play a role in these processes. Here, we report the characterization of multiple novel ethyl methanesulfonate (EMS)-induced nonsense alleles in the Drosophila LRRK2 homolog, lrrk. Using these alleles, we show that lrrk loss-of-function causes striking defects in the endolysosomal and autophagy pathways, including the accumulation of markedly enlarged lysosomes that are laden with undigested contents, consistent with a defect in lysosomal degradation. lrrk loss-of-function also results in the accumulation of autophagosomes, as well as the presence of enlarged early endosomes laden with mono-ubiquitylated cargo proteins, suggesting an additional defect in lysosomal substrate delivery. Interestingly, the lysosomal abnormalities in these lrrk mutants can be suppressed by a constitutively active form of the small GTPase rab9, which promotes retromer-dependent recycling from late endosomes to the Golgi. Collectively, our data provides compelling evidence of a vital role for lrrk in lysosomal function and endolysosomal membrane transport in vivo, and suggests a link between lrrk and retromer-mediated endosomal recycling.


Asunto(s)
Alelos , Autofagia , Proteínas de Drosophila/genética , Metanosulfonato de Etilo/química , Proteínas Serina-Treonina Quinasas/genética , Animales , Animales Modificados Genéticamente , Codón sin Sentido , Citosol/metabolismo , Proteínas de Drosophila/fisiología , Drosophila melanogaster , Endosomas/metabolismo , Femenino , Humanos , Etiquetado Corte-Fin in Situ , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Lisosomas/metabolismo , Microscopía Confocal , Microscopía Fluorescente , Mutación , Fenotipo , Proteínas Serina-Treonina Quinasas/fisiología
20.
Cell Death Dis ; 4: e924, 2013 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-24263098

RESUMEN

The failure of adult hippocampal neurogenesis is increasingly considered as an important factor in the pathological correlates for memory decline in Alzheimer's disease (AD). Loss of adult-born neurons and abnormalities of neural stem/progenitor cells (NSPCs) within the dentate gyrus (DG) of adult hippocampus might contribute to this process. In this study, we showed that amyloid-ß(1-42) (Aß42) oligomer triggers senescent phenotype of NSPCs in vitro. Oligomerized Aß42 induced the production of senescence-associated biomarkers p16 and senescence-associated ß-galactosidase (SA-ß-gal) in adult mouse hippocampal NSPCs, as well as inhibited cells proliferation and differentiation. In the DG of amyloid precursor protein/presenilin1 (APP/PS1) transgenic mice, the number of senescent NSPCs was significantly increased and senescence-associated protein p16 was upregulated. Formylpeptide receptor 2 (FPR2), one of Aß42 functional receptors, may be involved in NSPCs senescence. The FPR2 antagonist WRW4 significantly inhibited NSPCs senescence induced by Aß42. In addition, the activation of p38 mitogen-activated protein kinase (MAPK) in response to the accumulation of reactive oxygen species (ROS) was involved in NSPCs senescence induced by Aß42. WRW4 inhibited the accumulation of ROS and the activation of p38 MAPK in NSPCs. Our data suggest that Aß42 accelerates NSPCs senescence via FPR2-dependent activation of its downstream ROS-p38 MAPK signaling, which limits the function of NSPCs and contributes to failure of neurogenesis. This is the first demonstration of NSPCs senescence response to Aß42.


Asunto(s)
Péptidos beta-Amiloides/farmacología , Senescencia Celular/efectos de los fármacos , Hipocampo/citología , Células-Madre Neurales/citología , Células-Madre Neurales/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Receptores de Formil Péptido/metabolismo , Animales , Células Cultivadas , Masculino , Ratones , Ratones Endogámicos C57BL , Células-Madre Neurales/metabolismo , Oligopéptidos/farmacología , Especies Reactivas de Oxígeno/metabolismo , Receptores de Formil Péptido/antagonistas & inhibidores
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