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1.
J Acoust Soc Am ; 149(2): 983, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33639815

RESUMO

Real-time accurate channel estimation has been an ongoing challenge because of diverse oceanic events that cause rapid fluctuations of high-energy multipath activity across the delay spread. This work leverages current compressed sensing and sparse optimization techniques with topological signal processing to improve estimation time and localize channel estimation to salient parts of the delay spread. This work improves the estimation time by tracking the channel as a union of overlapping multipath and other scattering events, which are modeled as "feature braids" in the delay-time domain. A channel feature braid may be intuitively visualized as the topologically connected trajectory of a group of channel delay taps, which represent the support of dominant or persistent scattering events, e.g., surface bounce multipath scattering. We present algorithms that harness support-constrained mixed norm optimization techniques to track the evolving support of channel feature braids. We validate our channel feature tracking algorithm independently in experimental field data as well as BELLHOP channel simulations across a diversity of oceanic conditions. This work shows that braiding used in estimation can improve estimation time and track high-energy events that develop within the delay vs time channel representation.

2.
Hernia ; 22(5): 781-784, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30097796

RESUMO

PURPOSE: Given the difficulty of durable repairs, there is continued interest in hernia prevention. One emerging prevention technique for parastomal hernias is prophylactic mesh placement, whereby mesh is inserted during the index procedure as hernia prophylaxis. We evaluated our experience using prophylactic mesh when creating an ileal conduit. METHODS: We retrospectively reviewed patients undergoing robotic cystectomy with ileal conduit from 6/2010 to 8/2017. Patient demographics and operative/perioperative outcomes were documented. We evaluated hernia recurrence using postoperative computed tomography scanning or physical exam. Prophylactic mesh was inserted at the operating surgeon's discretion using a synthetic resorbable or biologic mesh. RESULTS: During the study period, 38 patients underwent robotic-assisted cystectomy with ileal conduit formation. Average patient age was 68 years, with 28 (74%) male and 35 (92%) Caucasian patients. Three patients (8%) required conversion to open, and one patient (3%) had a concomitant colorectal resection. Thirty-one (88%) patients had postoperative computed tomography scanning. Prophylactic mesh was used in 18 patients (47%) in a retrorectus position. Of these, 15 (83%) patients had synthetic resorbable mesh and 3 (17%) patients had biologic mesh. At average follow-up of 21 months, one hernia recurred (5%) in a patient without mesh placement at the time of ileal conduit. At an average follow-up of 11 months, there have been no recurrences and no mesh-related complications in the prophylactic mesh group. CONCLUSIONS: Using prophylactic mesh in ileal conduit, creation is feasible and may decrease the parastomal hernia formation rate. Further study of using synthetic resorbable and biologic meshes for hernia prophylaxis is warranted.


Assuntos
Cistectomia , Hérnia Ventral/prevenção & controle , Telas Cirúrgicas , Derivação Urinária , Idoso , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Estudos Retrospectivos , Estomas Cirúrgicos
3.
Cogn Neuropsychiatry ; 23(4): 229-241, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29865930

RESUMO

INTRODUCTION: Although there is evidence for language abnormality in schizophrenia, few studies have examined sign language in deaf patients with the disorder. This is of potential interest because a hallmark of sign languages is their use of classifiers (semantic or entity classifiers), a reference-tracking device with few if any parallels in spoken languages. This study aimed to examine classifier production and comprehension in deaf signing adults with schizophrenia. METHOD: Fourteen profoundly deaf signing adults with schizophrenia and 35 age- and IQ-matched deaf healthy controls completed a battery of tests assessing classifier and noun comprehension and production. RESULTS: The patients showed poorer performance than the healthy controls on comprehension and production of both nouns and entity classifiers, with the deficit being most marked in the production of classifiers. Classifier production errors affected handshape rather than other parameters such as movement and location. CONCLUSIONS: The findings suggest that schizophrenia affects language production in deaf patients with schizophrenia in a unique way not seen in hearing patients.


Assuntos
Compreensão/fisiologia , Surdez/complicações , Esquizofrenia/complicações , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem , Masculino , Pessoa de Meia-Idade , Semântica , Adulto Jovem
4.
Ir J Med Sci ; 185(3): 683-687, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26210881

RESUMO

INTRODUCTION: Although the role of vitamin D in the prevention of rickets has long been well established, controversies still exist on the ideal dose of vitamin D supplementation in infants. OBJECTIVE: We assessed serum 25-hydroxyvitamin D (25OHD) status simultaneously in maternal and cord samples and the response to vitamin D3 supplementation in neonates. METHODS: Serum 25OHD levels were evaluated from maternal, and umbilical cord samples from term normal pregnancies. Repeat 25OHD levels were assessed in neonates with 25OHD below 30 nmol/L following vitamin D3 200 IU daily after 6 weeks. RESULTS: Blood samples were taken including 57 cord samples and 16 follow-up neonatal samples. Maternal and cord serum 25OHD were 43 ± 21 and 29 ± 15 nmol/L, respectively. Infants with 25OHD < 30 nmol/L (19.8 ± 4.7 nmol/L) had a significant increase in serum 25OHD (63.3 ± 14.5 nmol/L) following vitamin D3 200 IU daily after 6 weeks. CONCLUSION: Healthy Irish infants born at term are at high risk of vitamin D deficiency, but vitamin D3 200 IU daily, rapidly corrects poor vitamin D status.


Assuntos
Colecalciferol/administração & dosagem , Suplementos Nutricionais , Deficiência de Vitamina D/dietoterapia , Vitaminas/administração & dosagem , Aleitamento Materno , Colecalciferol/deficiência , Feminino , Sangue Fetal/química , Humanos , Lactente , Fórmulas Infantis , Recém-Nascido , Masculino , Estudos Prospectivos , Estações do Ano , Resultado do Tratamento , Vitamina D/análogos & derivados , Vitamina D/sangue
5.
Epilepsy Behav ; 28(1): 71-7, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23665641

RESUMO

PURPOSE: Flashbulb memories (FMs) are vivid and stable autobiographical memories associated with learning surprising news of high emotional impact. Patients with temporal lobe epilepsy (TLE) can have autobiographical memory deficits. This is the first investigation of FMs in TLE applying a consistency measure of FM quality controlling for confabulation. METHOD: A sample of 12 patients with TLE and a matched group of 15 healthy controls (HCs) were tested on an FM test including a retest procedure. Scores of FM consistency were obtained by comparing answers across both testing occasions. RESULTS: In patients with TLE, FM consistency scores were significantly lower than in HCs. Exploratory subgroup analyses revealed FM deficits in both patients with left TLE and patients with right TLE compared with HCs. CONCLUSION: The present study indicates that the FMs of patients with TLE are less consistent than those of healthy control subjects. Future investigations with larger samples are desirable, especially regarding separate analyses of patients with left TLE and patients with right TLE.


Assuntos
Epilepsia do Lobo Temporal/complicações , Transtornos da Memória/etiologia , Memória de Curto Prazo/fisiologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Transtornos da Memória/diagnóstico , Pessoa de Meia-Idade , Transtornos do Humor/diagnóstico , Transtornos do Humor/etiologia , Análise Multivariada , Testes Neuropsicológicos , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Inquéritos e Questionários
6.
Ir Med J ; 104(6): 173-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22111393

RESUMO

This prospective Irish observational study examined maternal and infant nutritional supplement use. From an initial sample of 539 mothers recruited from the Coombe Women and Infants University Hospital in Dublin (during 2004-2006), 450 eligible mothers were followed up at 6 weeks and 6 months postpartum. Only 200 women (44.4%) complied with peri-conceptional folic acid at the recommended time with strong social patterning associated with its uptake. Almost 10% of the sample (n = 44) consumed a combined multivitamin and mineral supplement during pregnancy. A vitamin D-containing supplement was provided to only 5 (1.1%) and 15 (3.3%) infants at 6 weeks and 6 months, respectively. A national guideline that advises on adequate and safe use of both vitamin and multivitamin supplements during pregnancy with particular reference to vitamin A and D is warranted. Given the re-emergence of rickets in Ireland, and the reported morbidities associated with vitamin D insufficiency, promoting and monitoring compliance with 200 IU [5 microg] daily vitamin D supplements to all infants particularly those from higher risk groups from birth to 1 year, should be a public health priority.


Assuntos
Anormalidades Congênitas/prevenção & controle , Suplementos Nutricionais , Minerais/administração & dosagem , Distúrbios Nutricionais/prevenção & controle , Vitaminas/administração & dosagem , Adulto , Demografia , Feminino , Ácido Fólico/administração & dosagem , Prioridades em Saúde , Humanos , Lactente , Recém-Nascido , Irlanda , Modelos Logísticos , Observação , Gravidez , Estudos Prospectivos , Vitamina D/administração & dosagem
7.
Psychol Med ; 37(10): 1403-12, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17506924

RESUMO

BACKGROUND: A form of confabulation has been documented in schizophrenia and appears to be related to the symptom of thought disorder. It is unclear whether it is associated with the same pattern of neuropsychological deficits as confabulation in neurological patients. METHOD: Thirty-four patients with chronic schizophrenia, including those with and without thought disorder, and 17 healthy controls were given a fable recall task to elicit confabulation. They were also examined on a range of executive, episodic and semantic memory tests. RESULTS: Confabulation was seen at a significantly higher rate in the schizophrenic patients than the controls, and predominated in those with thought disorder. Neuropsychologically, it was not a function of general intellectual impairment, and was not clearly related to episodic memory or executive impairment. However, there were indications of an association with semantic memory impairment. CONCLUSIONS: The findings support the existence of a form of confabulation in schizophrenia that is related to thought disorder and has a different neuropsychological signature to the neurological form of the symptom.


Assuntos
Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/epidemiologia , Delusões/epidemiologia , Delusões/psicologia , Narração , Esquizofrenia/epidemiologia , Comportamento Verbal , Adulto , Feminino , Humanos , Masculino , Transtornos da Memória/diagnóstico , Transtornos da Memória/epidemiologia , Rememoração Mental , Testes Neuropsicológicos , Psicologia , Semântica , Índice de Gravidade de Doença
8.
Neurocase ; 8(3): 233-44, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12119320

RESUMO

It has been suggested that formal thought disorder, the incoherent speech of schizophrenia, may involve a language disturbance among other abnormalities, or even be a form of dysphasia. Six patients with and seven without formal thought disorder were evaluated on an aphasia test battery. Spontaneous speech was also analysed using Brief Syntactic Analysis. Poor performance on the aphasia test battery was found to be associated with general intellectual impairment but not with formal thought disorder. Naming was preserved in both groups. Patients with formal thought disorder, but not those without, produced semantic errors in their spontaneous speech, and these were unrelated to general intellectual status. The disorder of language in formal thought disorder thus appears to be one of expressive semantic abnormality, which, however, spares naming. Further analysis of two intellectually preserved patients suggested that formal thought disorder may be associated with an additional difficulty in constructing an appropriate model for generating one's own speech.


Assuntos
Linguagem do Esquizofrênico , Psicologia do Esquizofrênico , Pensamento/fisiologia , Adulto , Afasia/psicologia , Doença Crônica , Feminino , Humanos , Idioma , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Semântica
9.
Can J Vet Res ; 65(2): 125-30, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11346257

RESUMO

The primary objective of this study was to determine the effects of diets containing 18% or 34% protein on glomerular mesangial area (GMA) and basement membrane thickness (GBMT) in uninephrectomized aged dogs. A secondary objective was to determine the combined effects of aging and uninephrectomy on GMA and GBMT in dogs. Ten clinically healthy, pure-bred dogs were unilaterally nephrectomized at about 8 y of age. After 2 mo, 5 dogs were fed an 18% protein diet and 5 dogs were fed a 34% protein diet for 48 mo. At month 48, the dogs were euthanized and the remaining kidney was collected. Samples of kidney from both times of collection were used to measure GMA and GBMT using electron microscopy. The effects of diet on GMA and GBMT were analyzed (student's t-test) using necropsy/nephrectomy score ratios. The effects of time-nephrectomy were determined by comparing nephrectomy values for GMA and GBMT with necropsy values (paired t-test). Dogs fed 34% dietary protein did not have a significant increase in GMA and GBM thickness when compared to dogs fed the 18% protein diet. A significant increase in GMA and GBMT occurred with time-nephrectomy (P = 0.011 and 0.018, respectively). Although dietary protein intake was not a significant factor in causing structural changes to glomeruli in uninephrectomized aged dogs, the power to detect a difference was low. However, significant effects of aging and nephrectomy were detected despite the low power of the study. These results suggest that the increases in GMA and GBMT that occur over time are not markedly influenced by dietary protein intake. However, subtle protein effects cannot be eliminated as a possibility based on this study.


Assuntos
Envelhecimento/fisiologia , Proteínas Alimentares/administração & dosagem , Mesângio Glomerular/fisiologia , Rim/fisiologia , Animais , Membrana Basal/efeitos dos fármacos , Membrana Basal/fisiologia , Membrana Basal/ultraestrutura , Creatinina/urina , Cães , Mesângio Glomerular/efeitos dos fármacos , Mesângio Glomerular/ultraestrutura , Rim/efeitos dos fármacos , Rim/patologia , Necrose , Nefrectomia/veterinária , Proteinúria/veterinária , Reprodutibilidade dos Testes
10.
Neurocase ; 7(1): 77-87, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11239078

RESUMO

We describe our investigations of MNA, who had a progressive, severe and global loss of semantic knowledge (semantic dementia). Her verbal vocabulary was restricted to a few common words and she was also unable to recognize common objects from sight. By contrast, she had a well-preserved digit span (7-8 digits). In this series of experiments, we focused on her ability to repeat lists and sentences in which familiarity, meaningfulness, morphology and syntactic structure were manipulated. In list repetition tasks, we found that MNA showed a reliable effect of phonological similarity, word frequency and stimulus lexicality, but was unaffected by linguistic complexity, word length, semantic coherence or the status of individual stimuli as "known" or "unknown". In sentence repetition, her performance was not influenced by any semantic variables. However, there was a substantial effect of the frequency of the constituent vocabulary, even for words outside the range of her retained vocabulary. The influence of syntax was restricted to minor effects of morphology. The phonemes of syllables and the syllables of words are bound by their co-occurrence rather than their meaning. We conclude that the phonological representation of words is functionally independent of the semantic system.


Assuntos
Afasia/complicações , Afasia/fisiopatologia , Demência/complicações , Demência/fisiopatologia , Semântica , Idoso , Afasia/patologia , Atrofia/complicações , Atrofia/patologia , Atrofia/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Demência/patologia , Feminino , Humanos , Fonética , Análise e Desempenho de Tarefas
11.
Psychol Med ; 31(2): 197-205, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11232908

RESUMO

BACKGROUND: Although poor language test performance has been documented in schizophrenia, its relationship to formal thought disorder remains unclear. METHOD: Forty schizophrenic patients were administered eight language tests and, under blind conditions, rated for formal thought disorder. Measures of general intellectual function were also obtained. RESULTS: Performance on all language tests was significantly correlated with the general intellectual measures. Three language test scores also showed significant correlations with formal thought disorder scores. Multiple regression and analysis of intellectually preserved patients suggested particular associations of formal thought disorder with semantic comprehension and picture description. CONCLUSIONS: General intellectual impairment is an important determinant of poor language test performance in schizophrenia, but presence of formal thought disorder may also contribute. A higher-order semantic deficit may be particularly relevant to both linguistic impairment and formal thought disorder.


Assuntos
Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Transtornos da Linguagem/diagnóstico , Transtornos da Linguagem/etiologia , Esquizofrenia/complicações , Pensamento , Adulto , Idoso , Feminino , Humanos , Testes de Linguagem , Linguística , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Semântica , Índice de Gravidade de Doença
12.
Br J Psychol ; 92(Pt 1): 171-92, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11256762

RESUMO

Clinical and normal psychology have had a long tradition of close interaction in British psychology. The roots of this interplay may predate the development of the British Psychological Society, but the Society has encouraged and supported this line of research since its inception. One fundamental British insight has been to consider the evidence from pathology as a potential constraint on theories of normal function. In turn, theories of normal function have been used to understand and illuminate cognitive pathology. This review discusses some of the areas in which clinical contributions to cognitive theory have been most substantial. As with other contributions to this volume, attempts are also made to read the runes and anticipate future developments.


Assuntos
Encéfalo/fisiopatologia , Transtornos Cognitivos/fisiopatologia , Atenção/fisiologia , Dislexia/fisiopatologia , Lobo Frontal/fisiopatologia , História do Século XX , Memória/fisiologia , Teoria Psicológica , Psicologia/história , Reino Unido , Visão Ocular/fisiologia
13.
Dermatol Surg ; 27(2): 195-7, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11207698

RESUMO

BACKGROUND: A case of basal cell carcinoma (BCC) developing in the repair scar of a cleft lip is presented. OBJECTIVE: Primary BCCs arising in surgical scars are very rare and no known reported cases exist of a BCC developing in a surgically repaired cleft lip scar. METHODS: A 69-year-old white man presented with a 5 mm primary BCC on his upper lip at the site of his cleft lip repair scar. The diagnosis was made by a tangential biopsy that showed an ulcerated BCC. RESULTS: Review of the medical literature indicates that a scar may be an independent risk factor for developing BCC. CONCLUSION: BCC may rarely arise in a cleft lip repair scar.


Assuntos
Carcinoma Basocelular/complicações , Cicatriz/complicações , Fenda Labial/cirurgia , Neoplasias Labiais/complicações , Idoso , Carcinoma Basocelular/diagnóstico , Carcinoma Basocelular/patologia , Humanos , Neoplasias Labiais/diagnóstico , Neoplasias Labiais/patologia , Masculino
14.
Dermatol Surg ; 26(8): 723-7, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10940056

RESUMO

BACKGROUND: As hair removal technology continues to evolve and new equipment comes to market, conflicts may develop between dermatologists and electrologists regarding the professional control and use of these devices. METHODS: A total of 1004 Fellows of the American Academy of Dermatology and 719 electrologists from the southern United States were anonymously surveyed about clinical laser procedures (CLPs). RESULTS: Compared to electrologists, dermatologists were more likely to support clinical laser regulations that placed licensed physicians in control (P =.001) and preferred that a delegating physician be physically present on the premises when CLPs were performed (P =.001). If a laser device was invented for permanent hair removal that was identical to traditional needle/probe electrolysis in every respect except energy type ("laser fiberoptic probe," LFP), electrologists were more likely than dermatologists to support independent use of this device by electrologists (P =.001). A greater percentage of electrologists from Texas, a state without electrolysis licensing, were more likely to support the unlicensed use of the LFP and CLPs than electrologists from states requiring electrolysis licensing. CONCLUSIONS: These data are consistent with previously published literature and permit a greater understanding of the multiple attitudinal, regulatory, and ethical issues involved when considering delegated and independent CLPs by electrologists.


Assuntos
Pessoal Técnico de Saúde/normas , Atitude do Pessoal de Saúde , Dermatologia/normas , Remoção de Cabelo/normas , Terapia a Laser/normas , Licenciamento/normas , Médicos/psicologia , Florida , Humanos , Médicos/estatística & dados numéricos , Inquéritos e Questionários , Tennessee , Texas , Recursos Humanos
15.
Environ Health Perspect ; 108(3): 219-24, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10706527

RESUMO

Complete sex reversal of fish is accomplished routinely in aquaculture practices by exposing fish to exogenous sex steroids during gonadal differentiation. A variety of environmental chemicals are also active at sex steroid receptors and theoretically possess the potential to alter normal sexual differentiation in fish. However, in controlled environmental chemical exposures to date, only partial alterations of fish sexual phenotype have been observed. Here we report complete, permanent, and functional male-to-female sex reversal in the Japanese medaka (Oryzias latipes, d-rR strain) after a onetime embryonic exposure to the xenoestrogen o, p'-DDT. d-rR strain medaka are strict gonochorists that possesses both sex-linked pigmentation, which distinguishes genotypic sex, and sexually dimorphic external secondary sexual characteristics, which distinguish phenotypic sex. We directly microinjected the xenoestrogen o, p'-DDT into the egg yolks of medaka at fertilization to parallel the maternal transfer of lipophilic contaminants to the embryo. At 10 weeks of age, microinjected medaka were examined for mortality and sex reversal. A calculated embryonic dose of 511 +/- 22 ng/egg o, p'-DDT (mean +/- standard error) resulted in 50% mortality. An embryonic exposure of 227 +/- 22 ng/egg o, p'-DDT resulted in 86% (6 of 7) sex reversal of genetic males to a female phenotype (XY females). XY females were distinguished by sex-linked male pigmentation accompanying female secondary sexual characteristics. Histologic examination of the gonads confirmed active ovaries in 100% of the XY females. In 10-day breeding trials in which XY females were paired with normal XY males, 50% of the XY females produced fertilized embryos; this represents a comparable breeding success rate to normal XX females. Fertilized eggs produced from XY females hatched to viable larvae. These results clearly indicate that a weakly estrogenic pesticide, o, p'-DDT, when presented during the critical period of gonadal development, can profoundly alter sexual differentiation.


Assuntos
DDT/efeitos adversos , Gema de Ovo/efeitos dos fármacos , Estrogênios não Esteroides/efeitos adversos , Organismos Hermafroditas , Exposição Materna/efeitos adversos , Microinjeções , Processos de Determinação Sexual , Diferenciação Sexual/efeitos dos fármacos , Animais , Cruzamento , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Genótipo , Gônadas/efeitos dos fármacos , Gônadas/ultraestrutura , Masculino , Oryzias/genética , Fenótipo , Diferenciação Sexual/genética
16.
Brain ; 123 Pt 3: 472-83, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10686171

RESUMO

Patients with epilepsy frequently complain of memory difficulties yet perform normally on standard neuropsychological tests of memory. It has been suggested that this may be due to an impairment of very long-term memory consolidation processes, beyond those normally assessed in the neuropsychological clinic. We carried out a prospective study of verbal memory over a long-term retention interval of 8 weeks in patients with epilepsy and in controls. Results were compared with performance on conventional tests of memory. Despite normal learning and retention over 30 min, patients with epileptic foci in the left temporal lobe performed disproportionately poorly on the long-term test compared with both patients with epileptic foci in the right temporal lobe and controls. Our findings provide evidence for an extended period of memory consolidation and point to the critical region for this process, at least for verbal material, in the left temporal lobe. The implications of our findings for clinical assessment and therapeutic management of patients with epilepsy are discussed.


Assuntos
Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/fisiopatologia , Transtornos da Memória/etiologia , Transtornos da Memória/fisiopatologia , Adolescente , Adulto , Idoso , Análise de Variância , Dominância Cerebral/fisiologia , Feminino , Humanos , Masculino , Rememoração Mental/fisiologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Lobo Temporal/fisiopatologia , Aprendizagem Verbal
17.
Toxicon ; 37(12): 1827-32, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10519658

RESUMO

Ciguatoxins are lipophilic polyether toxins which concentrate in the viscera and flesh of coral reef associated finfish (Hessel et al., 1960). In this study, we quantify the adverse effects of ciguatoxin on fish embryos by microinjection into the egg yolk of medaka (Oryzias latipis) embryos. Embryos microinjected with 0.1-0.9 pg/egg (ppb) of ciguatoxin exhibit cardiovascular, muscular, and skeletal abnormalities and those injected with higher levels (1.0-9.0 pg/egg) exhibit significantly reduced hatching success. The sensitivity of embryonic fish to direct oocyte exposure indicates that maternal transfer of low levels of ciguatoxin may represent an unrecognized threat to the reproductive success of reef fish and a previously undetected ecological consequence of proliferation of ciguatoxin-producing algae in reef systems increasingly impacted by human perturbations.


Assuntos
Ciguatoxinas/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Oryzias/embriologia , Animais , Embrião não Mamífero/embriologia , Hipercinese/induzido quimicamente , Microinjeções , Curvaturas da Coluna Vertebral/induzido quimicamente , Taxa de Sobrevida , Taquicardia/induzido quimicamente
18.
Neuroreport ; 10(2): 255-9, 1999 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-10203318

RESUMO

Event-related brain potentials (ERPs) were recorded in response to unfamiliar faces and to houses from a severely prosopagnosic patient (PHD) and 24 control subjects. For all control subjects, faces elicited an enhanced negativity at lateral temporal electrodes (N170). This component was absent for PHD. Comparable results were obtained in response to inverted faces and houses. A selective deficit in face recognition is therefore reflected by abnormalities in ERP components specific to faces. As PHD was shown to have substantial deficits on tasks requiring the structural analysis of faces, these findings are consistent with the view that the N170 reflects processes involved in the structural encoding of faces, and may be a measure of selective impairments in the analysis of face components.


Assuntos
Agnosia/fisiopatologia , Face , Reconhecimento Visual de Modelos/fisiologia , Adulto , Agnosia/psicologia , Comportamento/fisiologia , Potenciais Evocados Visuais/fisiologia , Humanos , Masculino , Estimulação Luminosa , Valores de Referência
19.
Biol Bull ; 194(3): 281-96, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9664655

RESUMO

Embryonic levels of retinoic acid (RA) and the response of cells to RA are critical to the normal development of vertebrates. To understand the effects of RA signaling in Fundulus heteroclitus, we exposed embryos to a range of RA concentrations of 2 h during gastrulation. Embryos exposed to low concentrations of RA (10(-10)-10(-7) M) develop normally, whereas those exposed to higher concentrations (5 x 10(-7)-10(-4) M) develop characteristic dose-dependent defects. We describe, in detail, four stages of development that represent morphological effects of RA on (1) cell death and defects in the brain, heart, and eye, (2) relative size and differentiation, (3) duplications of pectoral fins, and (4) deletions in craniofacial cartilage elements. Analysis of cartilaginous skeletal elements demonstrates distinct patterns of deletions in the neurocranium and pharyngeal skeleton in response to increasing concentrations of RA. In F. heteroclitus, RA treatment during gastrulation results in five highly consistent phenotypes, which we have incorporated into an index of embryonic RA defects. This index should be valuable in the genetic analysis of RA pathways and in evaluating chemicals that interfere with embryonic RA signaling.


Assuntos
Anormalidades Craniofaciais/induzido quimicamente , Peixes Listrados/embriologia , Tretinoína/toxicidade , Animais , Padronização Corporal/efeitos dos fármacos , Padronização Corporal/fisiologia , Cartilagem/anormalidades , Cartilagem/efeitos dos fármacos , Cartilagem/embriologia , Anormalidades Craniofaciais/embriologia , Feminino , Gástrula/efeitos dos fármacos , Peixes Listrados/fisiologia , Masculino , Fenótipo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Tretinoína/administração & dosagem , Tretinoína/fisiologia
20.
Dev Genes Evol ; 208(2): 61-8, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9569347

RESUMO

Retinoic acid (RA), a derivative of vitamin A, plays a critical role as a signaling molecule in axial patterning of vertebrates. Here we report that RA exposure of zebrafish (Danio rerio) and mummichog (Fundulus heteroclitus) embryos during gastrulation results in homeotic duplications of the pectoral fins in up to 94% of fish. We have observed three to four pairs of fins in an individual fish. Although some duplications are partial, many represent complete axial duplications of the pectoral girdle and fin and include coracoscapulae, proximal radials, and dermal fin elements. Fin duplications are observed only at a defined dose of RA. Inhibition of RA synthesis by exposure to citral during a narrow developmental window leads to fish which lack pectoral fins but can be rescued by addition of exogenous RA, suggesting that RA signaling is critical to fin specification during early development. The ability to consistently induce multiple fins in a large number of vertebrate embryos should contribute to the understanding of genetic regulation of the normal positioning of limbs during embryogenesis.


Assuntos
Peixes/embriologia , Transdução de Sinais , Tretinoína/metabolismo , Animais , Padronização Corporal , Larva/efeitos dos fármacos , Larva/ultraestrutura , Deformidades Congênitas dos Membros/induzido quimicamente , Deformidades Congênitas dos Membros/metabolismo , Microscopia Eletrônica de Varredura , Teratogênicos/toxicidade , Tretinoína/toxicidade
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