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1.
Br J Dermatol ; 186(4): 694-704, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34773645

RESUMEN

BACKGROUND: For patients with early American Joint Committee on Cancer (AJCC)-stage melanoma the combined loss of the autophagy regulatory protein AMBRA1 and the terminal differentiation marker loricrin in the peritumoral epidermis is associated with a significantly increased risk of metastasis. OBJECTIVES: The aim of the present study was to evaluate the potential contribution of melanoma paracrine transforming growth factor (TGF)-ß signalling to the loss of AMBRA1 in the epidermis overlying the primary tumour and disruption of epidermal integrity. METHODS: Immunohistochemistry was used to analyse AMBRA1 and TGF-ß2 in a cohort of 109 AJCC all-stage melanomas, and TGF-ß2 and claudin-1 in a cohort of 30 or 42 AJCC stage I melanomas, respectively, with known AMBRA1 and loricrin (AMLo) expression. Evidence of pre-ulceration was analysed in a cohort of 42 melanomas, with TGF-ß2 signalling evaluated in primary keratinocytes. RESULTS: Increased tumoral TGF-ß2 was significantly associated with loss of peritumoral AMBRA1 (P < 0·05), ulceration (P < 0·001), AMLo high-risk status (P < 0·05) and metastasis (P < 0·01). TGF-ß2 treatment of keratinocytes resulted in downregulation of AMBRA1, loricrin and claudin-1, while knockdown of AMBRA1 was associated with decreased expression of claudin-1 and increased proliferation of keratinocytes (P < 0·05). Importantly, we show loss of AMBRA1 in the peritumoral epidermis was associated with decreased claudin-1 expression (P < 0·05), parakeratosis (P < 0·01) and cleft formation in the dermoepidermal junction (P < 0·05). CONCLUSIONS: Collectively, these data suggest a paracrine mechanism whereby TGF-ß2 causes loss of AMBRA1 overlying high-risk AJCC early-stage melanomas and reduced epidermal integrity, thereby facilitating erosion of the epidermis and tumour ulceration.


Asunto(s)
Melanoma , Neoplasias Cutáneas , Factor de Crecimiento Transformador beta2/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Epidermis/metabolismo , Humanos , Melanoma/patología , Neoplasias Cutáneas/patología , Factor de Crecimiento Transformador beta/metabolismo , Factores de Crecimiento Transformadores/metabolismo
2.
Br J Dermatol ; 182(1): 156-165, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31056744

RESUMEN

BACKGROUND: The updated American Joint Committee on Cancer (AJCC) staging criteria for melanoma remain unable to identify high-risk stage I tumour subsets. OBJECTIVES: To determine the utility of epidermal autophagy and beclin 1 regulator 1 (AMBRA1)/loricrin (AMLo) expression as a prognostic biomarker for AJCC stage I cutaneous melanoma. METHODS: Peritumoral AMBRA1 expression was evaluated in a retrospective discovery cohort of 76 AJCC stage I melanomas. AMLo expression was correlated with clinical outcomes up to 12 years in two independent powered, retrospective validation and qualification cohorts comprising 379 AJCC stage I melanomas. RESULTS: Decreased AMBRA1 expression in the epidermis overlying primary melanomas in a discovery cohort of 76 AJCC stage I tumours was associated with a 7-year disease-free survival (DFS) rate of 81·5% vs. 100% survival with maintained AMBRA1 (P < 0·081). Following an immunohistochemistry protocol for semi-quantitative analysis of AMLo, analysis was undertaken in validation (n = 218) and qualification cohorts (n = 161) of AJCC stage I melanomas. Combined cohort analysis revealed a DFS rate of 98·3% in the AMLo low-risk group (n = 239) vs. 85·4% in the AMLo high-risk cohort (n = 140; P < 0·001). Subcohort multivariate analysis revealed that an AMLo hazard ratio (HR) of 4·04 [95% confidence interval (CI) 1·69-9·66; P = 0·002] is a stronger predictor of DFS than Breslow depth (HR 2·97, 95% CI 0·93-9·56; P = 0·068) in stage IB patients. CONCLUSIONS: Loss of AMLo expression in the epidermis overlying primary AJCC stage I melanomas identifies high-risk tumour subsets independently of Breslow depth. What's already known about this topic? There is an unmet clinical need for biomarkers of early-stage melanoma. Autophagy and beclin 1 regulator 1 (AMBRA1) is a proautophagy regulatory protein with known roles in cell proliferation and differentiation, and is a known tumour suppressor. Loricrin is a marker of epidermal terminal differentiation. What does this study add? AMBRA1 has a functional role in keratinocyte/epidermal proliferation and differentiation. The combined decrease/loss of peritumoral AMBRA1 and loricrin is associated with a significantly increased risk of metastatic spread in American Joint Committee on Cancer (AJCC) stage I tumours vs. melanomas, in which peritumoral AMBRA1 and loricrin are maintained, independently of Breslow depth. What is the translational message? The integration of peritumoral epidermal AMBRA1/loricrin biomarker expression into melanoma care guidelines will facilitate more accurate, personalized risk stratification for patients with AJCC stage I melanomas, thereby facilitating stratification for appropriate follow-up and informing postdiagnostic investigations, including sentinel lymph node biopsy, ultimately resulting in improved disease outcomes and rationalization of healthcare costs.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Melanoma , Proteínas de la Membrana/genética , Neoplasias Cutáneas , Autofagia , Epidermis/patología , Humanos , Melanoma/patología , Estadificación de Neoplasias , Pronóstico , Estudios Retrospectivos , Neoplasias Cutáneas/patología , Estados Unidos
3.
Horm Behav ; 102: 1-9, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29630896

RESUMEN

Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11ß-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations.


Asunto(s)
Migración Animal/fisiología , Equidae/fisiología , Sistema Hipotálamo-Hipofisario/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Conducta Social , Animales , Conducta Competitiva/fisiología , Ecosistema , Heces/química , Conducta Alimentaria/fisiología , Femenino , Glucocorticoides/análisis , Glucocorticoides/metabolismo , Pradera , Masculino , Conducta Predatoria/fisiología , Embarazo , Estaciones del Año , Sudáfrica
4.
Osteoporos Int ; 27(1): 309-18, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26446770

RESUMEN

UNLABELLED: The cathepsin K inhibitor, ONO-5334, improves bone mineral density in postmenopausal women with osteoporosis. The effects of morning versus evening administration of ONO-5334 were investigated by measuring bone turnover marker levels in healthy postmenopausal women. Morning administration of ONO-5334 showed a more consistent suppressive effect on bone resorption than evening administration. INTRODUCTION: Bone turnover is thought to be subject to circadian variation, and the efficacy of osteoporosis treatments may be optimized by regulating the time of dosing. This study assessed whether evening administration of the cathepsin K inhibitor, ONO-5334, had a differential effect on the bone turnover marker, C-terminal telopeptide of type I collagen (CTX-I), compared with morning administration. METHODS: This was a single-center, single blind crossover study. Fourteen healthy postmenopausal women were assigned to receive ONO-5334 150 mg once daily for 5 days in each period; they were randomized to receive either evening doses in the first period and morning doses in the second or vice versa. Serum and urinary levels of CTX-I were measured throughout the study. RESULTS: Both regimens showed similar patterns of reduction in serum and urinary CTX-I; however, CTX-I suppression was more consistently >60% over 24 h following morning administration. Morning administration led to 6% greater suppression of 24-h serum CTX-I area under the effect curve (AUE; 69 vs 63%; P < .05) and 7% greater suppression of urinary CTX-I/creatinine AUE (93 vs 86%; P < .01) than evening administration. Higher plasma ONO-5334 concentrations were observed between 12 and 24 h postdose following morning administration, with mean trough concentrations for the morning and evening regimens at 9.4 and 4.0 ng/mL, respectively. There were no safety findings of concern. CONCLUSION: Morning dosing of ONO-5334 is more efficacious at reducing markers of bone turnover in healthy postmenopausal women than evening dosing. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01384188 , registered on June 27, 2011 EudraCT: 2008-006284-37.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Resorción Ósea/prevención & control , Catepsina K/antagonistas & inhibidores , Tiazolidinas/administración & dosificación , Anciano , Biomarcadores/sangre , Conservadores de la Densidad Ósea/farmacología , Conservadores de la Densidad Ósea/uso terapéutico , Resorción Ósea/sangre , Resorción Ósea/fisiopatología , Relojes Circadianos/fisiología , Colágeno Tipo I/sangre , Estudios Cruzados , Esquema de Medicación , Femenino , Humanos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/prevención & control , Péptidos/sangre , Posmenopausia/sangre , Posmenopausia/fisiología , Método Simple Ciego , Tiazolidinas/farmacología , Tiazolidinas/uso terapéutico
5.
Phys Rev Lett ; 112(13): 135001, 2014 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-24745431

RESUMEN

A strong nonhydrodynamic mechanism generating atomic fuel-shell mix has been observed in strongly shocked inertial confinement fusion implosions of thin deuterated-plastic shells filled with 3He gas. These implosions were found to produce D3He-proton shock yields comparable to implosions of identical shells filled with a hydroequivalent 50∶50 D3He gas mixture. Standard hydrodynamic mixing cannot explain this observation, as hydrodynamic modeling including mix predicts a yield an order of magnitude lower than was observed. Instead, these results can be attributed to ion diffusive mix at the fuel-shell interface.

6.
Heredity (Edinb) ; 107(2): 155-66, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21304547

RESUMEN

Animal pigment patterns are important for a range of functions, including camouflage and communication. Repeating pigment patterns, such as stripes, bars and spots have been of particular interest to developmental and theoretical biologists, but the genetic basis of natural variation in such patterns is largely unexplored. In this study, we identify a difference in a periodic pigment pattern among juvenile threespine sticklebacks (Gasterosteus aculeatus) from different environments. Freshwater sticklebacks exhibit prominent vertical bars that visually break up the body shape, but sticklebacks from marine populations do not. We hypothesize that these distinct pigment patterns are tuned to provide crypsis in different habitats. This phenotypic difference is widespread and appears in most of the freshwater populations that we sampled. We used quantitative trait locus (QTL) mapping in freshwater-marine F2 hybrids to elucidate the genetic architecture underlying divergence in this pigmentation pattern. We identified two QTL that were significantly associated with variation in barring. Interestingly, these QTL were associated with two distinct aspects of the pigment pattern: melanophore number and overall pigment level. We compared the QTL locations with positions of known pigment candidate genes in the stickleback genome. We also identified two major QTL for juvenile body size, providing new insights into the genetic basis of juvenile growth rates in natural populations. In summary, although there is a growing literature describing simple genetic bases for adaptive coloration differences, this study emphasizes that pigment patterns can also possess a more complex genetic architecture.


Asunto(s)
Fenotipo , Pigmentación/genética , Smegmamorpha/genética , Alelos , Animales , Tamaño Corporal/genética , Mapeo Cromosómico , Femenino , Masculino , Pigmentos Biológicos/genética , Sitios de Carácter Cuantitativo/genética
7.
J Exp Biol ; 213(4): 613-20, 2010 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-20118312

RESUMEN

Despite the key function of the Mauthner cells (M-cells) in initiating escape responses and thereby promoting survival, there are multiple examples of M-cell loss across the teleost phylogeny. Only a few studies have directly considered the behavioral consequences of naturally occurring M-cell variation across species. We chose to examine this issue in pufferfishes, as previous research suggested that there might be variability in M-cell anatomy in this group of fish. We characterized the M-cell anatomy and fast-start responses of two pufferfish species, Tetraodon nigroviridis and Diodon holocanthus. T. nigroviridis showed robust fast-starts to both tactile and acoustic startling stimuli. These fast-starts occurred with a latency typical of M-cell initiation in other fish, and retrograde labeling of spinal-projection neurons revealed that T. nigroviridis does have M-cells. By contrast, D. holocanthus only rarely exhibited fast-start-like behavior, and these responses were at a substantially longer latency and were much less extensive than those of T. nigroviridis. Using three complementary anatomical techniques we were unable to identify obvious M-cell candidates in D. holocanthus. These results provide a clear correlation between M-cell presence or absence and dramatic differences in fast-start behavior. The rich diversity within the pufferfish clade should allow future studies investigating the factors that contribute to this correlated anatomical and behavioral variation.


Asunto(s)
Reflejo de Sobresalto , Tetraodontiformes/anatomía & histología , Tetraodontiformes/fisiología , Animales , Reacción de Fuga , Neuroanatomía
8.
Ultrason Sonochem ; 55: 25-31, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31084788

RESUMEN

This paper describes a two-step method to prepare novel copper-methanol nanofluids capped with a short chain molecule, (3-Aminopropyl)trimethoxysilane (APTMS). Two commercial nanopowders were dispersed at various powers using a 20 kHz ultrasonic probe into solutions of methanol and the capping agent. Ultrasonic energy input was measured by calorimetry with z-average diameters, intensity and number size distributions recorded by a dynamic light scattering technique. The stability of the dispersion was monitored visually, and quantified by recording the zeta potential. Dispersions of the bare powder were used as a control. Absorption spectroscopy was used to confirm the presence of the capping agent. The thermal conductivities of 0 to 10% wt./vol. (1.1% vol.) dispersions of the capped copper-methanol nanofluid were determined using a C-Therm analyzer. Optimum ultrasonic de-agglomeration conditions gave dispersions with a z-average particle size of <200 nm and a PdI of <0.2. The capped particles showed good stability; up to six months in some instances, and an average zeta potential of +38 mV was recorded. The thermal conductivity of the nanofluid increased with concentration, and an enhancement of 9% over the base fluid was found at 10% wt./vol. (1.1% vol.). This innovative work has demonstrated the ultrasonic preparation and stability of copper nanoparticles protected with APTMS; a short chain molecule which binds to copper and prevents oxidation. The protected particles can enhance the thermal conductivity of methanol with no interference from the capping ligand.

9.
Open Access J Sports Med ; 10: 81-86, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31213934

RESUMEN

Introduction: Real tennis is a growing, unique, and well-established sport. To date, there has been no epidemiological data on real tennis injuries. The primary aim of this retrospective study is to record the incidence and document any trends in real tennis musculoskeletal injuries, so as to improve injury awareness of common and possibly preventable injuries. Methods: A surveillance questionnaire e-mailed to 2,036 Tennis & Rackets Association members to retrospectively capture injuries sustained by amateur and professional real tennis players over their playing careers. Results: A total of 485 (438 males and 47 females) questionnaires were fully completed over 4 weeks. A total of 662 musculoskeletal injuries were recorded with a mean of 1.4 injuries per player (range 0-7). The incidence of sustaining an acute real tennis musculoskeletal injury is 0.4/1000 hrs. The three main anatomical locations reported injured were elbow 15.6% (103/662), knee 11.6% (77/662), and face 10.0% (66/662). The most common structures reported injured were muscle 24% (161/661), tendon 23.4% (155/661), ligament 7.0% (46/661), soft tissue bruising 6.5% (43/661), and eye 6.2% (41/661). The majority of the upper limb injuries were gradual onset (64.7%, 143/221), and the lower limb injuries were sudden onset (72.0%, 188/261). Conclusion: This study uniquely provides valuable preliminary data on the incidence and patterns of musculoskeletal injuries in real tennis players. In addition, it highlights a number of reported eye injuries. The study is also a benchmark for future prospective studies on academy and professional real tennis players.

10.
Mol Biol Cell ; 10(3): 581-96, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10069805

RESUMEN

Recent cloning of a rat brain phosphatidylinositol 3,4, 5-trisphosphate binding protein, centaurin alpha, identified a novel gene family based on homology to an amino-terminal zinc-binding domain. In Saccharomyces cerevisiae, the protein with the highest homology to centaurin alpha is Gcs1p, the product of the GCS1 gene. GCS1 was originally identified as a gene conditionally required for the reentry of cells into the cell cycle after stationary phase growth. Gcs1p was previously characterized as a guanosine triphosphatase-activating protein for the small guanosine triphosphatase Arf1, and gcs1 mutants displayed vesicle-trafficking defects. Here, we have shown that similar to centaurin alpha, recombinant Gcs1p bound phosphoinositide-based affinity resins with high affinity and specificity. A novel GCS1 disruption strain (gcs1Delta) exhibited morphological defects, as well as mislocalization of cortical actin patches. gcs1Delta was hypersensitive to the actin monomer-sequestering drug, latrunculin-B. Synthetic lethality was observed between null alleles of GCS1 and SLA2, the gene encoding a protein involved in stabilization of the actin cytoskeleton. In addition, synthetic growth defects were observed between null alleles of GCS1 and SAC6, the gene encoding the yeast fimbrin homologue. Recombinant Gcs1p bound to actin filaments, stimulated actin polymerization, and inhibited actin depolymerization in vitro. These data provide in vivo and in vitro evidence that Gcs1p interacts directly with the actin cytoskeleton in S. cerevisiae.


Asunto(s)
Actinas/metabolismo , Actinas/ultraestructura , Proteínas de Unión al ADN/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas de Unión al GTP/metabolismo , Proteínas Activadoras de GTPasa , Proteínas de Microfilamentos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Factor 1 de Ribosilacion-ADP , Factores de Ribosilacion-ADP , Secuencia de Aminoácidos , Animales , Sitios de Unión , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Proteínas del Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Citoesqueleto/ultraestructura , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Eliminación de Gen , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Datos de Secuencia Molecular , Mutación , Fosfatidilinositoles/metabolismo , Ratas , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/genética , Homología de Secuencia de Aminoácido , Zinc/metabolismo , Dedos de Zinc
11.
J Wildl Dis ; 43(3): 399-407, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17699078

RESUMEN

Although well known as a widespread parasitic disease of columbids and birds of prey, there have been few studies of trichomonosis in populations of wild birds. In Mauritius, trichomonosis has been highlighted as a major threat to an endangered endemic, the Pink Pigeon (Neosoenas [Columba] mayeri). In this study, we examined the role that populations of other columbids in Mauritius might be playing as infectious reservoirs of the causal flagellate protozoan, Trichomonas gallinae. We screened 296 wild individuals of three columbid species (Madagascan Turtle Dove [Streptopelia picturata], Spotted Dove [Streptopelia chinensis], and Zebra Dove [Geopelia striata]) between September 2002 and April 2004. Prevalence varied significantly among species (ranging from 19% in S. chinensis to 59% in G. striata) and between S. picturata sampled from upland and coastal sites; S. picturata from upland sites (>500 m) were significantly less likely to be infected with T. gallinae than those from lowland sites (<50 m; 62% and 27% prevalence, respectively). There was no significant difference in the prevalence of T. gallinae at sites where Pink Pigeons were also present compared to those sampled at sites without Pink Pigeons. We show that T. gallinae infection prevalence is higher at sites and times of warmer temperatures and lower rainfall.


Asunto(s)
Enfermedades de las Aves/epidemiología , Columbidae/parasitología , Tricomoniasis/veterinaria , Animales , Conservación de los Recursos Naturales , Reservorios de Enfermedades/parasitología , Reservorios de Enfermedades/veterinaria , Mauricio/epidemiología , Estaciones del Año , Especificidad de la Especie , Trichomonas , Tricomoniasis/epidemiología
12.
Chem Commun (Camb) ; (1): 85-7, 2006 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-16353101

RESUMEN

We report a simple and efficient technique for the covalent immobilisation of a tris(2,2'-bipyridyl)ruthenium(II) derivative suitable for both chemiluminescence and electrochemiluminescence detection.

13.
Ann R Coll Surg Engl ; 98(6): 413-8, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27079259

RESUMEN

Introduction The aim of this study was to establish the prevalence of pelvic floor symptoms in women referred to a colorectal two-week wait (2WW) clinic with suspected colorectal cancer. Methods A questionnaire assessing faecal incontinence (FI) (Wexner score) and obstructed defecation syndrome (ODS) (Renzi score) was offered to 98 consecutive female patients attending a colorectal 2WW clinic at a single trust. Results Overall, 56 (57%) of the 98 patients had significant ODS and/or FI (scores >9/20), 33 (34%) had ODS and 40 (41%) had FI. Seventeen patients (17%) had both ODS and FI. Analysis of the 63 patients referred with a change in bowel habit (CIBH) showed 40 (63%) to be Renzi and/or Wexner positive compared with 16 (46%) of the 35 patients who presented without CIBH (p=0.095, Fisher's exact test). Further analysis showed that 31 (78%) of the 40 patients with FI presented with CIBH compared with 32 (55%) of the 58 without FI (p=0.032). In terms of ODS, 23 (70%) of the 33 patients with ODS presented with CIBH compared with 40 (62%) of the 65 without ODS (p=0.506). Conclusions Over half of the female patients attending our colorectal 2WW clinic had significant pelvic floor dysfunction (FI/ODS), which may account for their symptoms (especially in the CIBH referral category). While it is important for malignancy to be excluded, many patients may benefit from investigation and management of their pelvic floor dysfunction as the cause for their presenting symptoms.


Asunto(s)
Neoplasias Colorrectales/diagnóstico , Estreñimiento/etiología , Incontinencia Fecal/etiología , Trastornos del Suelo Pélvico/diagnóstico , Adulto , Enfermedades del Sistema Digestivo/diagnóstico , Detección Precoz del Cáncer , Femenino , Humanos , Trastornos del Suelo Pélvico/epidemiología , Prevalencia , Derivación y Consulta , Encuestas y Cuestionarios , Reino Unido
14.
J Neurosci ; 21(21): 8523-37, 2001 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11606641

RESUMEN

Epilepsy is a common outcome of traumatic brain injury (TBI), but the mechanisms of posttraumatic epileptogenesis are poorly understood. One clue is the occurrence of selective hippocampal cell death after fluid-percussion TBI in rats, consistent with the reported reduction of hippocampal volume bilaterally in humans after TBI and resembling hippocampal sclerosis, a hallmark of temporal-lobe epilepsy. Other features of temporal-lobe epilepsy, such as long-term seizure susceptibility, persistent hyperexcitability in the dentate gyrus (DG), and mossy fiber synaptic reorganization, however, have not been examined after TBI. To determine whether TBI induces these changes, we used a well studied model of TBI by weight drop on somatosensory cortex in adult rats. First, we confirmed an early and selective cell loss in the hilus of the DG and area CA3 of hippocampus, ipsilateral to the impact. Second, we found persistently enhanced susceptibility to pentylenetetrazole-induced convulsions 15 weeks after TBI. Third, by applying GABA(A) antagonists during field-potential and optical recordings in hippocampal slices 3 and 15 weeks after TBI, we unmasked a persistent, abnormal APV-sensitive hyperexcitability that was bilateral and localized to the granule cell and molecular layers of the DG. Finally, using Timm histochemistry, we detected progressive sprouting of mossy fibers into the inner molecular layers of the DG bilaterally 2-27 weeks after TBI. These findings are consistent with the development of posttraumatic epilepsy in an animal model of impact head injury, showing a striking similarity to the enduring behavioral, functional, and structural alterations associated with temporal-lobe epilepsy.


Asunto(s)
Lesiones Encefálicas/fisiopatología , Hipocampo/patología , Hipocampo/fisiopatología , Convulsiones/fisiopatología , 2-Amino-5-fosfonovalerato/farmacología , Animales , Lesiones Encefálicas/complicaciones , Recuento de Células , Muerte Celular , Enfermedad Crónica , Giro Dentado/efectos de los fármacos , Giro Dentado/patología , Giro Dentado/fisiopatología , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades/fisiopatología , Estimulación Eléctrica , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Antagonistas del GABA/farmacología , Antagonistas de Receptores de GABA-A , Técnicas In Vitro , Masculino , Fibras Musgosas del Hipocampo/patología , Fibras Musgosas del Hipocampo/fisiopatología , Plasticidad Neuronal , Pentilenotetrazol , Vía Perforante/efectos de los fármacos , Vía Perforante/fisiopatología , Ratas , Ratas Sprague-Dawley , Esclerosis/etiología , Esclerosis/patología , Convulsiones/etiología , Heridas no Penetrantes
15.
Cytogenet Genome Res ; 110(1-4): 553-8, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16093708

RESUMEN

Non-LTR retrotransposons are a diverse and taxonomically widely dispersed group of retroelements that can be divided into at least 14 distinguishable clades. Basal metazoans have not been examined in great detail for their retrotransposon content. In order to screen for the presence of reverse transcriptase (RT) related sequences in Cnidaria and Ctenophora, basal phyla of metazoans, PCR with highly degenerate oligonucleotides was performed and an RT-like sequence was identified from the sea anemone species Anemonia sulcata. Further screening identified a related element in another anemone species Actinia equina. Significant homology to non-LTR retrotransposon RTs was observed, particularly to L2-like elements of fish such as Maui. The sequence was not detected among other cnidarians and we have designated the A. sulcata and A. equina elements Abyss1 and Abyss2 respectively. Phylogenetic analysis of Abyss1 compared with members of 14 known non-LTR retroelement clades suggests that the sequence represents a novel L2 element.


Asunto(s)
Anémonas de Mar/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Southern Blotting , Secuencia de Consenso , ADN/genética , ADN/aislamiento & purificación , Cartilla de ADN , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Retroelementos , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico
16.
J Mol Biol ; 234(3): 894-6, 1993 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-8254683

RESUMEN

A complex between an Fab fragment of an E2 specific feline infectious peritonitis virus neutralizing antibody 730.1.4 and Fab fragment from anti-idiotypic monoclonal antibody 409.5.3, was crystallized from ammonium sulfate using vapor diffusion methods. The complex crystals diffract to about 2.9 A resolution and are of orthorhombic space group P2(1)22(1) with a = 75.2 A, b = 80.6 A and c = 187.6 A. There are two Fab molecules, or one idiotype-anti-idiotype complex, comprising the asymmetric unit. The long 187.6 A c axis suggests that the long axis of the complex might lie along this direction. Although small and radiation-sensitive, crystals are suitable for three-dimensional structural analysis.


Asunto(s)
Anticuerpos Antiidiotipos/metabolismo , Anticuerpos Antivirales/metabolismo , Coronavirus Felino/inmunología , Fragmentos Fab de Inmunoglobulinas/metabolismo , Animales , Anticuerpos Antiidiotipos/química , Anticuerpos Antivirales/química , Gatos , Cristalografía por Rayos X , Fragmentos Fab de Inmunoglobulinas/química , Conformación Proteica , Difracción de Rayos X
17.
J Mol Biol ; 235(5): 1560-84, 1994 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-8107092

RESUMEN

The structure of pig pancreatic alpha-amylase has been determined by X-ray diffraction analysis using multiple isomorphous replacement in a crystal of space group P2(1)2(1)2(1) (a = 70.6 A, b = 114.8 A, c = 118.8 A) containing nearly 75% solvent. The structure was refined by simulated annealing and Powell minimization, as monitored by 2Fo-Fc difference Fourier syntheses, to a conventional R of 0.168 at 2.1 A resolution. The final model consists of all 496 amino acid residues, a chloride and a calcium ion, 145 water molecules and an endogenous disaccharide molecule that contiguously links protein molecules related by the 2(1) crystallographic operator along x. The protein is composed of a large domain (amino acid residues 1 to 403) featuring a central alpha ta-barrel of eight parallel strands and connecting helices with a prominent excursion between strand beta 3 and helix alpha 3 (amino acid residues 100 to 168). The final 93 amino acid residues at the carboxyl terminus form a second small domain consisting of a compact Greek key beta-barrel. The domains are tightly associated through hydrophobic interfaces. The beta 3/alpha 3 excursion and portions of the central alpha/beta-barrel provide four protein ligands to the tightly bound Ca ion; three water molecules complete the coordination. The Cl- ion is bound within one end of the alpha/beta-barrel by two arginine residues in a manner suggesting a plausible mechanism for its allosteric activation of the enzyme. A crystalline complex of the pancreatic alpha-amylase with alpha-cyclodextrin, a cyclic substrate analog of six glucose residues, reveals, in difference Fourier maps, three unique binding sites. One of the alpha-cyclodextrin sites is near the center of the long polysaccharide binding cleft that traverses one end of the alpha/beta-barrel, another is at the extreme of this cleft. By symmetry this can also be considered as two half sites located at the extremes of the active site cleft. This latter alpha-cyclodextrin displaces the endogenous disaccharide when it binds and, along with the first sugar ring, delineates the extended starch binding site. The third alpha-cyclodextrin binds at an "accessory site" near the edge of the protein and is quite distant from the polysaccharide binding cleft. Its presence explains the multivalency of alpha-amylase binding to dextrins in solution. The extended active site cleft is formed by large, sweeping, connecting loops at one end of the alpha/beta-barrel. These include three sequence segments that are highly conserved among alpha-amylases.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Páncreas/enzimología , Conformación Proteica , Estructura Secundaria de Proteína , alfa-Amilasas/química , Animales , Sitios de Unión , Calcio/metabolismo , Cloruros/metabolismo , Gráficos por Computador , Cristalización , Cristalografía por Rayos X/métodos , Disacáridos/metabolismo , Enlace de Hidrógeno , Modelos Moleculares , Porcinos , alfa-Amilasas/aislamiento & purificación , alfa-Amilasas/metabolismo
18.
J Mol Biol ; 222(1): 17-9, 1991 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-1942064

RESUMEN

A monoclonal antibody of the subclass IgG2a specific for canine lymphoma cells has been crystallized by vapor diffusion from polyethylene glycol 8000. the crystals, which occasionally measure nearly a millimeter on edge, have been examined by X-ray diffraction. The crystals are of triclinic space group P1 with unit cell parameters of a = 66.39 A, b = 77.34 A, c = 101.42 A, alpha = 87.60 degrees, beta = 92.55 degrees, gamma = 97.54 degrees and cell volume of V = 4.84 x 10(5) A3. There is one entire antibody molecule as the asymmetric unit of the crystals. Three-dimensional X-ray diffraction data have been collected to 2.8 A resolution and a self rotation function calculation shows a pronounced peak indicating at least an approximate non-crystallographic dyad axis.


Asunto(s)
Anticuerpos Monoclonales/ultraestructura , Anticuerpos Antineoplásicos/ultraestructura , Inmunoglobulina G/ultraestructura , Linfoma/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antineoplásicos/inmunología , Cristalización , Perros , Inmunoglobulina G/inmunología , Difracción de Rayos X
19.
J Mol Biol ; 277(1): 37-59, 1998 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-9514737

RESUMEN

The molecular structure of satellite tobacco mosaic virus (STMV) has been refined to 1.8 A resolution using X-ray diffraction data collected from crystals grown in microgravity. The final R value was 0.179 and Rfree was 0.184 for 219,086 independent reflections. The final model of the asymmetric unit contained amino acid residues 13 to 159 of a coat protein monomer, 21 nucleotides, a sulfate ion, and 168 water molecules. The nucleotides were visualized as 30 helical segments of nine base-pairs with an additional base stacked at each 3' end, plus a "free" nucleotide, not belonging to the helical segments, but firmly bound by the protein. Sulfate ions are located exactly on 5-fold axes and each is coordinated by ten asparagine side-chains. Of the 10,080 structural waters, 168 per asymmetric unit, about 20% serve to bridge the macromolecular components at protein-protein and protein-nucleic acid interfaces. Binding of RNA to the protein involves some salt linkages, particularly to the phosphate of the free nucleotide, but the major contribution is from an intricate network of hydrogen bonds. There are numerous water molecules in the RNA-protein interface, many serving as intermediate hydrogen bond bridges. The sugar-phosphate backbone contributes most of the donors and acceptors for the RNA. The helical RNA conformation is nearest that of A form DNA. The central region of a helical segment is most extensively involved in contacts with protein, and exhibits low thermal parameters which increase dramatically toward the ends. The visible RNA represents approximately 59% of the total nucleic acid in the virion and is derived from the single-stranded genome, which has folded upon itself to form helical segments. Linking of the helices and the free nucleotides in a contiguous and efficient manner severely restricts the disposition of the remaining, unseen nucleic acid. Using the remaining nucleotides it is possible to fold the RNA according to motifs that provide a periodic distribution of RNA structural elements compatible with the icosahedrally symmetrical arrangement seen in the crystallographic structure. The intimate relationship between protein and nucleic acid in STMV suggests an assembly pathway based on the cooperative and coordinated co-condensation of RNA with capsid protein dimers.


Asunto(s)
Virus Satélite del Mosaico del Tabaco/química , Secuencia de Aminoácidos , Cápside/química , Enlace de Hidrógeno , Modelos Moleculares , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Estructura Secundaria de Proteína , ARN Viral/química , Proteínas de Unión al ARN/química , Sulfatos/química , Virión/química , Agua/química , Difracción de Rayos X
20.
J Mol Biol ; 222(3): 445-6, 1991 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-1660922

RESUMEN

The Fab fragment of an antibody, made against an E2-specific feline infectious peritonitis virus neutralizing antibody, has been crystallized in a form suitable for X-ray diffraction analysis from PEG 4000 using vapor diffusion methods. The Fab fragment crystals diffract to about 2.9 A resolution and are of triclinic space group P1. Unit cell dimensions, by which the reciprocal lattice can be indexed, are a = 57.16 A, b = 70.85 A, c = 75.81 A, alpha = 85.11 degrees, beta = 121.28 degrees and gamma = 116.33 degrees. There are two Fab fragments comprising the asymmetric unit of the crystals. The presence of a pseudo-mirror plane in the diffraction pattern suggests the presence of at least an approximate dyad axis relating the two Fab fragments within the asymmetric unit.


Asunto(s)
Anticuerpos Monoclonales/química , Coronavirus Felino/inmunología , Cristalografía , Fragmentos Fab de Inmunoglobulinas/química , Animales , Cristalización , Ratones
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