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In this study, we propose a mathematical model of self-propelled objects based on the Allen-Cahn type phase-field equation. We combine it with the equation for the concentration of surfactant used in previous studies to construct a model that can handle self-propelled object motion with shape change. A distinctive feature of our mathematical model is that it can represent both deformable self-propelled objects, such as droplets, and solid objects, such as camphor disks, by controlling a single parameter. Furthermore, we demonstrate that, by taking the singular limit, this phase-field based model can be reduced to a free boundary model, which is equivalent to the [Formula: see text]-gradient flow model of self-propelled objects derived by the variational principle from the interfacial energy, which gives a physical interpretation to the phase-field model.
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AIM: The telomere is a structure present at the ends of chromosomes, and is known to shorten with aging and successive rounds of cell division. However, very little is known about telomere attrition in post-mitotic cells, such as neurons. METHODS: Using our originally developed quantitative fluorescence in situ hybridization method, we analyzed age-dependent alterations of telomere length in three types of cells in the human cerebrum: neurons and glial cells in both the gray and white matter. RESULTS: In adults, telomeres were significantly longer in neurons than in glial cells, whereas in infants, telomere lengths did not differ among the three cell types. No aging-related telomere attrition was evident in neurons. However, the telomeres of glial cells were shorter in older individuals than in younger individuals, and attrition was more rapid in the white matter than in the gray matter. CONCLUSIONS: The present results suggest that the telomeres of neurons remain stable throughout life, whereas telomeres in white matter glial cells become significantly shorter with age. Examination of adults showed no significant correlation between telomere length and age in the three cell types. Although the present study was cross-sectional, the results suggest that telomere shortening before adolescence contributes to the significant decrease of telomere length in white matter glial cells. The present findings in normal cerebral tissues will be informative for future studies of telomere stability in the diseased brain. Geriatr Gerontol Int 2018; 18: 1507-1512.
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Envejecimiento/genética , Longevidad/genética , Neuroglía/patología , Neuronas/patología , Telómero/patología , Factores de Edad , Anciano , Anciano de 80 o más Años , Biopsia con Aguja , Células Cultivadas , Preescolar , Estudios Transversales , Femenino , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Lactante , Recién Nacido , Masculino , Factores de Riesgo , Sensibilidad y Especificidad , Técnicas de Cultivo de TejidosRESUMEN
Telomeres maintain the integrity of chromosome ends and telomere length is an important marker of aging. The epidemiological studies suggested that many types of stress including psychosocial stress decrease telomere length. However, it remains unknown how various stresses induce telomere shortening. Here, we report that the stress-responsive transcription factor ATF7 mediates TNF-α-induced telomere shortening. ATF7 and telomerase, an enzyme that elongates telomeres, are localized on telomeres via interactions with the Ku complex. In response to TNF-α, which is induced by various stresses including psychological stress, ATF7 was phosphorylated by p38, leading to the release of ATF7 and telomerase from telomeres. Thus, a decrease of ATF7 and telomerase on telomeres in response to stress causes telomere shortening, as observed in ATF7-deficient mice. These findings give credence to the idea that various types of stress might shorten telomere.
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Factores de Transcripción Activadores/fisiología , Acortamiento del Telómero , Factor de Necrosis Tumoral alfa/fisiología , Factores de Transcripción Activadores/genética , Factores de Transcripción Activadores/metabolismo , Animales , Fibroblastos , Células HeLa , Histonas/metabolismo , Humanos , Autoantígeno Ku/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación , Telomerasa/metabolismo , Telómero/metabolismoRESUMEN
In the original publication of this article, Fig. 5 was published with incorrect color of the approximate lines of CBD and Control.
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BACKGROUND: Congenital biliary dilatation (CBD) is a congenital malformation involving both dilatation of the extrahepatic bile duct and pancreaticobiliary maljunction. Persistent reflux of pancreatic juice injures the biliary tract mucosa, resulting in chronic inflammation and higher rates of carcinogenesis in the biliary tract, including the gallbladder. Telomeres are repetitive DNA sequences located at the ends of chromosomes. Chromosomal instability due to telomere dysfunction plays an important role in the carcinogenesis of many organs. This study was performed to determine whether excessive shortening of telomeres occurs in the gallbladder mucosa of patients with CBD. METHODS: Resected gallbladders were obtained from 17 patients with CBD, ten patients with cholecystolithiasis without pancreatic juice reflux, and 17 patients with normal gallbladders (controls) (median age of each group of patients: 37, 50, and 53 years, respectively). The telomere lengths of the gallbladder epithelium were measured by quantitative fluorescence in situ hybridization using tissue sections, and the normalized telomere-to-centromere ratio (NTCR) was calculated. RESULTS: The NTCRs in the CBD, cholecystolithiasis, and control groups were 1.24 [interquartile range (IQR) 1.125-1.52], 1.96 (IQR 1.56-2.295), and 1.77 (IQR 1.48-2.53), respectively. The NTCR in the CBD group was significantly smaller than that in the cholecystolithiasis and control groups (p = 0.003 and 0.004, respectively), even in young patients. CONCLUSIONS: Our findings indicate that telomere shortening in the gallbladder mucosa plays an important role in the process of carcinogenesis in patients with CBD. These results support the recommendation of established guidelines for prophylactic surgery in patients with CBD because CBD is a premalignant condition with excessive telomere shortening.
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Conductos Biliares Extrahepáticos/anomalías , Vesícula Biliar/patología , Conductos Pancreáticos/anomalías , Acortamiento del Telómero , Adulto , Conductos Biliares Extrahepáticos/diagnóstico por imagen , Neoplasias del Sistema Biliar/diagnóstico por imagen , Neoplasias del Sistema Biliar/genética , Colangiopancreatografia Retrógrada Endoscópica , Pancreatocolangiografía por Resonancia Magnética , Conducto Colédoco/anomalías , Conducto Colédoco/diagnóstico por imagen , Dilatación Patológica/congénito , Dilatación Patológica/diagnóstico por imagen , Dilatación Patológica/genética , Epitelio/patología , Femenino , Humanos , Hibridación Fluorescente in Situ , Masculino , Persona de Mediana Edad , Conductos Pancreáticos/diagnóstico por imagen , Lesiones Precancerosas/diagnóstico por imagen , Lesiones Precancerosas/genética , Tomografía Computarizada por Rayos XRESUMEN
A variant in a transcription factor gene, POU4F3, is responsible for autosomal dominant nonsyndromic hereditary hearing loss, DFNA15. To date, 14 variants, including a whole deletion of POU4F3, have been reported to cause HL in various ethnic groups. In the present study, genetic screening for POU4F3 variants was carried out for a large series of Japanese hearing loss (HL) patients to clarify the prevalence and clinical characteristics of DFNA15 in the Japanese population. Massively parallel DNA sequencing of 68 target candidate genes was utilized in 2,549 unrelated Japanese HL patients (probands) to identify genomic variations responsible for HL. The detailed clinical features in patients with POU4F3 variants were collected from medical charts and analyzed. Novel 12 POU4F3 likely pathogenic variants (six missense variants, three frameshift variants, and three nonsense variants) were successfully identified in 15 probands (2.5%) among 602 families exhibiting autosomal dominant HL, whereas no variants were detected in the other 1,947 probands with autosomal recessive or inheritance pattern unknown HL. To obtain the audiovestibular configuration of the patients harboring POU4F3 variants, we collected audiograms and vestibular symptoms of the probands and their affected family members. Audiovestibular phenotypes in a total of 24 individuals from the 15 families possessing variants were characterized by progressive HL, with a large variation in the onset age and severity with or without vestibular symptoms observed. Pure-tone audiograms indicated the most prevalent configuration as mid-frequency HL type followed by high-frequency HL type, with asymmetry observed in approximately 20% of affected individuals. Analysis of the relationship between age and pure-tone average suggested that individuals with truncating variants showed earlier onset and slower progression of HL than did those with non-truncating variants. The present study showed that variants in POU4F3 were a common cause of autosomal dominant HL.
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Pueblo Asiatico/genética , Pérdida Auditiva Sensorineural/genética , Proteínas de Homeodominio/genética , Factor de Transcripción Brn-3C/genética , Adolescente , Adulto , Anciano , Niño , Preescolar , Codón sin Sentido , ADN/química , ADN/metabolismo , Femenino , Mutación del Sistema de Lectura , Frecuencia de los Genes , Pérdida Auditiva Sensorineural/patología , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Lactante , Recién Nacido , Japón , Masculino , Persona de Mediana Edad , Mutación Missense , Linaje , Polimorfismo Genético , Análisis de Secuencia de ADN , Adulto JovenRESUMEN
Understanding the details of the electronic structure in face-to-face arranged tetrathiafulvalenes (TTFs) is very important for the design of supramolecular functional materials and superior conductive organic materials. This article is a comprehensive study of the interactions among columnar stacked TTFs using trimeric (trimer) and tetrameric (tetramer) TTFs linked by alkylenedithio groups (-S(CH2 )n S-, n=1-4) as models of triple- and quadruple-decker TTF arrays. Single-crystal X-ray analyses of neutral trimeric TTFs revealed that the three TTF moieties are oriented in a zigzag arrangement. Cyclic voltammetry measurements (CV) reveal that the trimer and tetramer exhibited diverse reversible redox processes with multi-electron transfers, depending on the length of the -S(CH2 )n S- units and substituents. The electronic spectra of the radical cations, prepared by electrochemical oxidation, showed charge resonance (CR) bands in the NIR/IR region (1630-1850â nm), attributed to a mixed valence (MV) state of the triple- and quadruple-decker TTF arrays. In the trimeric systems, the dicationic state (+2; 0.66 cation per TTF unit) was found to be a stable state, whereas the monocationic state (+1) was not observed in the electronic spectra. In the tetrameric system, substituent-dependent redox processes were observed. Moreover, π-trimers and π-tetramers, which show a significant Davydov blueshift in the spectra, are formed in the tricationic (trimer) and tetracationic (tetramer) state. In addition, these attractive interactions are strongly dependent on the length of the linkage unit.
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We have reported telomere attrition in ß and α cells of the pancreas in elderly patients with type 2 diabetes, but it has not been explored how the telomere lengths of these islet cells change according to age in normal subjects. To examine the telomere lengths of ß and α cells in individuals without diabetes across a wide range of ages, we conducted measurement of the telomere lengths of human pancreatic ß and α cells obtained from 104 autopsied subjects without diabetes ranging in age from 0 to 100 years. As an index of telomere lengths, the normalized telomere-centromere ratio (NTCR) was determined for ß (NTCRß) and α (NTCRα) cells by quantitative fluorescence in situ hybridization (Q-FISH). We found NTCRß and NTCRα showed almost the same levels and both decreased according to age (p < 0.001 for both). NTCRs decreased more rapidly with age and were more widely distributed (p = 0.036 for NTCRß, p < 0.001 for NTCRα) in subjects under 18 years of age than in subjects over 18 years. There was a positive correlation between NTCRß and NTCRα only among adult subjects (p < 0.001). In conclusion, the telomeres of ß and α cells become shortened with normal aging process.
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Envejecimiento/genética , Diabetes Mellitus Tipo 2/genética , Células Secretoras de Glucagón/metabolismo , Células Secretoras de Insulina/metabolismo , Telómero/genética , Adulto , Anciano , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Femenino , Estudios de Seguimiento , Células Secretoras de Glucagón/patología , Humanos , Hibridación Fluorescente in Situ , Células Secretoras de Insulina/patología , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
Accumulated data have shown that most human somatic cells or tissues show irreversible telomere shortening with age, and that there are strong associations between telomere attrition and aging-related diseases, including cancers, diabetes and cognitive disorders. Although it has been largely accepted that telomere attrition is one of the major causes of aging-related disorders, critical aspects of telomere biology remain unresolved, especially the lack of standardized methodology for quantification of telomere length. Another frustrating issue is that no potentially promising methods for safe prevention of telomere erosion, or for telomere elongation, have been devised. Here, we review several methods for quantification of telomere length currently utilized worldwide, considering their advantages and drawbacks. We also summarize the results of our recent studies of human cells and tissues, mainly using quantitative fluorescence in situ hybridization and Southern blotting, including those derived from patients with progeria-prone Werner syndrome and trisomy 21, and several strains of induced pluripotent stem cells. We discuss the possible merits of using telomere shortness as an indicator, or a new marker, for diagnosis of precancerous states and aging-related disorders. In addition, we describe newly found factors that are thought to impact telomere dynamics, providing a new avenue for examining the unsolved issues related to telomere restoration and maintenance.
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Envejecimiento/genética , Homeostasis del Telómero/fisiología , Telómero/fisiología , Southern Blotting , Humanos , Hibridación Fluorescente in SituRESUMEN
We examined nitrification in the euphotic zone, its impact on the nitrogen cycles, and the controlling factors along a 7500 km transect from the equatorial Pacific Ocean to the Arctic Ocean. Ammonia oxidation occurred in the euphotic zone at most of the stations. The gene and transcript abundances for ammonia oxidation indicated that the shallow clade archaea were the major ammonia oxidizers throughout the study regions. Ammonia oxidation accounted for up to 87.4% (average 55.6%) of the rate of nitrate assimilation in the subtropical oligotrophic region. However, in the shallow Bering and Chukchi sea shelves (bottom ⩽67 m), the percentage was small (0-4.74%) because ammonia oxidation and the abundance of ammonia oxidizers were low, the light environment being one possible explanation for the low activity. With the exception of the shallow bottom stations, depth-integrated ammonia oxidation was positively correlated with depth-integrated primary production. Ammonia oxidation was low in the high-nutrient low-chlorophyll subarctic region and high in the Bering Sea Green Belt, and primary production in both was influenced by micronutrient supply. An ammonium kinetics experiment demonstrated that ammonia oxidation did not increase significantly with the addition of 31-1560 nm ammonium at most stations except in the Bering Sea Green Belt. Thus, the relationship between ammonia oxidation and primary production does not simply indicate that ammonia oxidation increased with ammonium supply through decomposition of organic matter produced by primary production but that ammonia oxidation might also be controlled by micronutrient availability as with primary production.
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Archaea/metabolismo , Nitrificación , Ciclo del Nitrógeno , Amoníaco/metabolismo , Archaea/genética , Regiones Árticas , Oxidación-Reducción , Océano PacíficoRESUMEN
Telomere shortening occurs when cells divide, both in vitro and in vivo. On the other hand, telomerase is able to maintain telomere length in cells by adding TTAGGG repeats to the ends of telomeres. However, the interrelationships existing among telomere length, telomerase activity and growth in vertebrates remain to be clarified. In the present study we measured telomere length (terminal restriction fragment length), telomerase activity and body growth of Oryzias latipes from the embryo stage until senescence. During the rapid growth stage (age 0-7 months), telomeres shortened in parallel with decreasing telomerase activity. Then, during adolescence (age 7 months - 1 year), telomeres lengthened quickly as growth slowed and telomerase activity increased. In the adult stage (age 1-4 years) characterized by little growth, telomerase activity decreased gradually and telomeres shortened. Our data indicate that telomere attrition and restoration are linked to growth and telomerase activity, and suggest that critical loss of telomere homeostasis is associated with mortality in this animal.
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Proteínas de Peces/metabolismo , Oryzias/metabolismo , Telomerasa/metabolismo , Homeostasis del Telómero , Acortamiento del Telómero , Telómero/metabolismo , Factores de Edad , Animales , Cinética , Estadios del Ciclo de Vida , Oryzias/genética , Oryzias/crecimiento & desarrollo , Telómero/genéticaRESUMEN
BACKGROUND: Blue nevus is a benign dermal melanocyte tumor that mainly arises from the skin. We report an extremely rare case of blue nevus in a pediatric patient with extensive progression from the middle ear and inner ear to the nasopharynx through the Eustachian tube. CASE REPORT: A 2-year-old girl with blue tympanum was referred to our department. Computed tomography scans and magnetic resonance imaging were performed, followed by a tissue biopsy and histopathologic evaluations. Radiologic examinations revealed that the lesion had progressed beyond the middle ear into the inner ear and the nasopharynx through the Eustachian tube. Subsequent histopathologic examinations indicated dermal dendritic melanocytic proliferations, but no evidence of malignancy. Based on the clinical and histopathologic findings, we concluded that the lesion was consistent with blue nevus. DISCUSSION: Blue nevus is a relatively common skin lesion. However, no prior reports have described the extension of blue nevus from the auditory organ to the nasopharynx in a pediatric patient. Despite the benign nature of the lesion, the patient experienced profound hearing loss in the affected ear, which necessitates continued monitoring as the lesion may expand with patient growth.
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Oído Medio/patología , Pérdida Auditiva Unilateral , Nasofaringe/patología , Nevo Azul , Neoplasias Cutáneas , Perforación de la Membrana Timpánica , Audiometría de Tonos Puros/métodos , Biopsia , Proliferación Celular , Preescolar , Diagnóstico Diferencial , Progresión de la Enfermedad , Oído Interno/patología , Trompa Auditiva/patología , Potenciales Evocados Auditivos del Tronco Encefálico , Femenino , Pérdida Auditiva Unilateral/diagnóstico , Pérdida Auditiva Unilateral/etiología , Humanos , Células de Langerhans/patología , Imagen por Resonancia Magnética/métodos , Melanocitos/patología , Monitoreo Fisiológico , Nevo Azul/complicaciones , Nevo Azul/patología , Nevo Azul/fisiopatología , Neoplasias Cutáneas/complicaciones , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/fisiopatología , Tomografía Computarizada por Rayos X/métodos , Perforación de la Membrana Timpánica/diagnóstico , Perforación de la Membrana Timpánica/etiologíaRESUMEN
A large body of evidence supports a key role for telomere dysfunction in carcinogenesis due to the induction of chromosomal instability. To study telomere shortening in precancerous pancreatic lesions, we measured telomere lengths using quantitative fluorescence in situ hybridization in the normal pancreatic duct epithelium, pancreatic intraepithelial neoplasias (PanINs), and cancers. The materials employed included surgically resected pancreatic specimens without cancer (n = 33) and with invasive ductal carcinoma (n = 36), as well as control autopsy cases (n = 150). In comparison with normal ducts, telomere length was decreased in PanIN-1, -2 and -3 and cancer. Furthermore, telomeres were shorter in cancer than in PanIN-1 and -2. Telomere length in cancer was not associated with histological type, lesion location, or cancer stage. PanINs with or without cancer showed similar telomere lengths. The incidences of atypical mitosis and anaphase bridges, which are morphological characteristics of chromosomal instability, were negatively correlated with telomere length. The telomeres in normal duct epithelium became shorter with aging, and those in PanINs or cancers were shorter than in age-matched controls, suggesting that telomere shortening occurs even when histological changes are absent. Our data strongly suggest that telomere shortening occurs in the early stages of pancreatic carcinogenesis and progresses with precancerous development. Telomere shortening and chromosomal instability in the duct epithelium might be associated with carcinogenesis of the pancreas. Determination of telomere length in pancreatic ductal lesions may be valuable for accurate detection and risk assessment of pancreatic cancer.
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Carcinoma in Situ/patología , Inestabilidad Cromosómica/genética , Epitelio/patología , Páncreas/patología , Neoplasias Pancreáticas/patología , Acortamiento del Telómero , Telómero/patología , Carcinoma in Situ/genética , Carcinoma in Situ/metabolismo , Epitelio/metabolismo , Humanos , Páncreas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Telómero/genéticaAsunto(s)
Factores de Edad , Tolerancia Inmunológica , Fallo Hepático/cirugía , Trasplante de Hígado , Donadores Vivos , Adulto , Biopsia , Abuelos , Humanos , Terapia de Inmunosupresión , Inmunosupresores/uso terapéutico , Incidencia , Padres , Proyectos Piloto , Tolerancia al Trasplante , Resultado del TratamientoRESUMEN
We have reported that telomere fluorescence units (TFUs) of established induced pluripotent stem cells (iPSCs) derived from human amnion (hAM933) and fetal lung fibroblasts (MRC-5) were significantly longer than those of the parental cells, and that the telomere extension rates varied quite significantly among clones without chromosomal instability, although the telomeres of other iPSCs derived from MRC-5 became shorter as the number of passages increased along with chromosomal abnormalities from an early stage. In the present study we attempted to clarify telomere dynamics in each individual chromosomal arm of parental cells and their derived clonal human iPSCs at different numbers of passages using quantitative fluorescence in situ hybridization (Q-FISH). Although no speciï¬c arm of any particular chromosome appeared to be consistently shorter or longer than most of the other chromosomes in any of the cell strains, telomere elongation in each chromosome of an iPSC appeared to be random and stochastic. However, in terms of the whole genome of any specific cell, the telomeres showed overall elongation associated with iPSC generation. We have thus demonstrated the specific telomere dynamics of each individual chromosomal arm in iPSCs derived from parental cells, and in the parental cells themselves, using Q-FISH.
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Aberraciones Cromosómicas , Cromosomas/ultraestructura , Células Madre Pluripotentes Inducidas/ultraestructura , Telómero/ultraestructura , Células Cultivadas , Cromosomas/genética , Diploidia , Humanos , Hibridación Fluorescente in Situ , Telomerasa/metabolismo , Telómero/genéticaRESUMEN
In the past decade, the serum free light chain (FLC) immunoassays have become widely available enabling greater sensitivity in the diagnosis and management of monoclonal light chain diseases. Here, we describe a rare case of serum free light chain only myeloma with cytoplasmic IgM. A 75-year-old woman presented with a progressively worsening lumbosacral pain. FDG PET/CT images showed increased FDG uptake in the sacral mass, vertebral bodies, and ribs. Laboratory data found hypogammaglobulinemia and the bone marrow aspirate revealed only 2.2% of plasma cells. The serum and urine protein electrophoresis did not detect a monoclonal band. However, the serum FLC immunoassays reported an abnormal kappa/lambda ratio (0.001) indicating the presence of monoclonal lambda FLC. The sacral tumor biopsy revealed proliferation of plasma cells and immunohistochemical staining showed that the plasma cells were positive for CD138, IgM, and lambda light chain but negative for CD20. This case may have previously been described as a nonsecretory IgM myeloma but recently would be identified as free light chain only myeloma. The immunohistochemical and genetic features of the clonal plasma cells in free light chain only myeloma need to be further investigated to better understand the relevance and incidence of this myeloma type.
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Ataxia telangiectasia is a neurodegenerative inherited disease with chromosomal instability and hypersensitivity to ionizing radiation. iPS cells lacking ATM (AT-iPS cells) exhibited hypersensitivity to X-ray irradiation, one of the characteristics of the disease. While parental ataxia telangiectasia cells exhibited significant chromosomal abnormalities, AT-iPS cells did not show any chromosomal instability in vitro for at least 80 passages (560 days). Whole exome analysis also showed a comparable nucleotide substitution rate in AT-iPS cells. Taken together, these data show that ATM is involved in protection from irradiation-induced cell death.
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Ataxia Telangiectasia/patología , Inestabilidad Cromosómica/efectos de la radiación , Exoma/genética , Células Madre Pluripotentes Inducidas/citología , Tolerancia a Radiación/genética , Teratoma/patología , Animales , Apoptosis/efectos de la radiación , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/radioterapia , Proteínas de la Ataxia Telangiectasia Mutada/genética , Western Blotting , Diferenciación Celular/efectos de la radiación , Proliferación Celular/efectos de la radiación , Células Cultivadas , Reprogramación Celular , Niño , Técnica del Anticuerpo Fluorescente , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Técnicas para Inmunoenzimas , Hibridación Fluorescente in Situ , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/efectos de la radiación , Cariotipificación , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Teratoma/genética , Teratoma/radioterapia , Rayos XRESUMEN
Background. Pleomorphic adenoma (PA) is a benign tumour that mainly arises from salivary glands, and PA of the external auditory canal (EAC) is very rare. The objective of this study was to clarify the clinical presentation and treatment of PA of the EAC. Method. The authors present a case of PA arising from the EAC together with a literature review. Results. A 40-year-old man complained of hearing loss and foreign-body sensation of the right ear. Clinical and radiological examinations revealed a well-defined tumour limited to the EAC, with no connection to the parotid gland. Preoperative fine-needle aspiration cytology findings were characteristic of PA. The tumour was removed en bloc with the overlying skin. Conclusion. PA of the EAC is very rare, and methods to rule out malignancy before treatment are lacking. Thus, long-term follow-up is necessary, because malignant tumours are common in the EAC and PA has malignant potential.
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Along with the increasing need for living-donor liver transplantation (LDLT), the issue of organ shortage has become a serious problem. Therefore, the use of organs from elderly donors has been increasing. While the short-term results of LDLT have greatly improved, problems affecting the long-term outcome of transplant patients remain unsolved. Furthermore, since contradictory data have been reported with regard to the relationship between donor age and LT/LDLT outcome, the question of whether the use of elderly donors influences the long-term outcome of a graft after LT/LDLT remains unsettled. To address whether hepatocyte telomere length reflects the outcome of LDLT, we analyzed the telomere lengths of hepatocytes in informative biopsy samples from 12 paired donors and recipients (grafts) of pediatric LDLT more than 5 years after adult-to-child LDLT because of primary biliary atresia, using quantitative fluorescence in situ hybridization (Q-FISH). The telomere lengths in the paired samples showed a robust relationship between the donor and grafted hepatocytes (râ=â0.765, pâ=â0.0038), demonstrating the feasibility of our Q-FISH method for cell-specific evaluation. While 8 pairs showed no significant difference between the telomere lengths for the donor and the recipient, the other 4 pairs showed significantly shorter telomeres in the recipient than in the donor. Multiple regression analysis revealed that the donors in the latter group were older than those in the former (pâ=â0.001). Despite the small number of subjects, this pilot study indicates that donor age is a crucial factor affecting telomere length sustainability in hepatocytes after pediatric LDLT, and that the telomeres in grafted livers may be elongated somewhat longer when the grafts are immunologically well controlled.