RESUMO
Seven patients with craniosynostosis (mean age 8 years, Apert syndrome, n = 4, Crouzon's disease, n = 3) underwent lengthening of the skull by gradual bone distraction. Three patients (group A) were treated by coronal craniectomy reaching the orbital fissure and gradual bone distraction. The other four (group B) underwent monobloc craniofacial disjunction and gradual bone distraction. The patients' progress was monitored clinically as well as by radiographs and photographs. The results showed that craniofacial disjunction followed by gradual bone distraction produced complete correction of exophthalmus and an improvement in the functional and aesthetic aspects of the middle third of the face without the need for bone grafts.
Assuntos
Alongamento Ósseo , Craniossinostoses/cirurgia , Acrocefalossindactilia/cirurgia , Cefalometria , Criança , Craniossinostoses/complicações , Exoftalmia/etiologia , Exoftalmia/cirurgia , Feminino , Humanos , Masculino , Resultado do TratamentoRESUMO
Artificial neural networks can represent and handle information by means of interconnected processing elements, in a manner similar to that of biologic neurons. Artificial neural networks are useful in processing time-patterned biologic signals, such as electrocardiograms and electroencephalograms, particularly in tasks involving pattern classification and recognition. They do not need to be programmed, since they are capable of learning. Using artificial neural networks to build associative memories and perform true parallel processing permits "intelligent" biomedical instrumentation.
Assuntos
Eletrocardiografia/instrumentação , Eletroencefalografia/instrumentação , Redes Neurais de Computação , Processamento de Sinais Assistido por Computador , Inteligência Artificial , Sistemas Inteligentes , Humanos , SoftwareRESUMO
The gel of silicone implants may bleed through the elastomeric envelope or may come into contact with the body because of rupture of the implant. We have studied the effects of free silicone gel injected into the subcutaneous space in rats and analysed the morphological features of the axillary and inguinal lymph nodes. Ninety six Wistar rats had 3 cm3 of silicone gel injected into their subcutaneous space and 96 Wistar rats (the control group) had distilled water injected into their subcutaneous space. The animals were killed on days 1,3,7,9,15, 30,60,90,120,180,270, and 365 after the injection. There was no detectable silicone and no damage to the lymph nodes on routine histopathological analysis. Small amounts of silicone that could migrate to lymph nodes could result in hyperplasia. To evaluate this possibility, a morphometric study based on a computer aided system compared the area of lymph node sections between treated and control animals, and showed no difference between treated and control groups. If silicone did migrate, it did not provoke morphological signs or hyperplasia in the lymph nodes.
Assuntos
Linfonodos/efeitos dos fármacos , Próteses e Implantes , Elastômeros de Silicone/farmacologia , Animais , Técnicas Histológicas , Hiperplasia , Processamento de Imagem Assistida por Computador , Injeções Subcutâneas , Linfonodos/patologia , Masculino , Ratos , Ratos Wistar , Elastômeros de Silicone/administração & dosagemRESUMO
OBJECTIVES: This study sought to assess the usefulness and accuracy of artificial neural networks in the prognosis of 1-year mortality in patients with heart failure. BACKGROUND: Artificial neural networks is a computational technique used to represent and process information by means of networks of interconnected processing elements, similar to neurons. They have found applications in medical decision support systems, particularly in prognosis. METHODS: Clinical and Doppler-derived echocardiographic data from 95 consecutive patients with diffuse impairment of myocardial contractility were studied. After 1 year, data regarding survival or death were obtained and produced the prognostic variable. The data base was divided randomly into a training data set (47 cases, 8 deaths) and a testing data set (48 cases, 7 deaths). Results of artificial neural network classification were compared with those from linear discriminant analysis, clinical judgment and conventional heuristically based programs. RESULTS: The study group included 57 male (47 survivors) and 38 female patients (33 survivors). Linear discriminant analysis was not efficient for separating survivors from nonsurvivors because the accuracy at the ideal cutoff value was only 67.4%, with a sensitivity of 67.5%, positive predictive value of 27.8% and negative predictive value of 91.5%. In contrast, all artificial neural networks were able to predict outcome with an accuracy of 90%, specificity of 93% and sensitivity of 71.4%, for the best artificial neural network. Both clinical judgment and automatic heuristic methods were also inferior in performance. CONCLUSIONS: The artificial neural network method has proved to be reliable for implementing quantitative prognosis of mortality in patients with heart failure. Additional studies with larger numbers of patients are required to better assess the usefulness of artificial neural networks.
Assuntos
Ecocardiografia , Insuficiência Cardíaca/mortalidade , Redes Neurais de Computação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Insuficiência Cardíaca/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Sensibilidade e EspecificidadeRESUMO
Male Wistar rats were tested for sensitivity to audiogenic seizures (AS; 110 dB), using an audiogenic severity index (SI). Sensitive (S) animals were subjected to bilateral lesion of the inferior colliculus (IC) and/or the lateral lemniscus (LL). Resistant (R) animals were subjected to bilateral lesions of the IC, unilateral sequential lesions of the substantia nigra reticulata (SN) and/or IC (contralateral to one another), and unilateral thalamic and sham lesions. Bilateral lesions of the IC and LL abolish AS in S rats. Lesion of the SN resulted in more pronounced sensitivity to AS than unilateral lesion of IC, in R rats. When the SN lesion was contralateral to a previous IC lesion, the effect was not only an increase in the SI, but also a reversal of the asymmetry generated by IC lesion. Although the behavioral effects resulting from IC lesions are due to alterations in the primary structures involved in the origin of AS, unilateral SN lesions can alter critical substrates of sensorimotor integration involved in the control and expression of AS.
Assuntos
Percepção Auditiva/fisiologia , Colículos Inferiores/fisiopatologia , Convulsões/fisiopatologia , Substância Negra/fisiopatologia , Estimulação Acústica , Animais , Córtex Auditivo/fisiologia , Vias Auditivas/fisiologia , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Corpos Geniculados/fisiologia , Masculino , Ratos , Ratos EndogâmicosRESUMO
Wistar-derived male rats were tested for audiogenic seizure (AS) susceptibility, and classified into sensitive (S) and resistant (R) groups. Rats from group R underwent unilateral ablation of the telencephalon, or were detelencephalated (HD), or sham-lesioned, and were tested for audiogenic susceptibility one month and one year after surgery. It was found that previously AS-resistant, HD-operated animals developed generalized tonic-clonic convulsions upon high intensity (110.8 dB) acoustic stimulation, with higher severity and shorter latencies than the susceptible, non-operated control animals. Sham-lesioned R animals maintained their previous resistance to AS. HD-lesioned R animals also presented asymmetric motor patterns, such as gyrating and barrel-rolling behavior, always oriented towards the side contralateral to the lesion. HD-lesioned S animals presented an increase in the severity of seizures, as well as a shortening of the latencies of the running (procursive) and convulsive phases of the seizures. This effect was more marked one year after surgery. Contralateral barrel-rolling behavior was also observed in these animals. The fact that seizure severity increases and latency decreases with time after lesion seems to indicate a role for denervation hypersensitivity and other cerebral plasticity phenomena in explaining the effects of HD lesions on AS. The fundamental neural structures involved appear to be those related to sensorimotor coordinating systems (substantia nigra/pontine-mesencephalic reticular formation and substantia nigra/superior colliculus), the acoustic pathways (inferior colliculus) and their projections to the superior colliculus and reticular formation.
Assuntos
Percepção Auditiva/fisiologia , Convulsões/fisiopatologia , Telencéfalo/fisiopatologia , Estimulação Acústica , Animais , Mapeamento Encefálico , Tronco Encefálico/fisiopatologia , Dominância Cerebral/fisiologia , Masculino , Plasticidade Neuronal , Ratos , Ratos Endogâmicos , Reflexo de Sobressalto/fisiologia , Comportamento Estereotipado/fisiologiaRESUMO
1. A stereotaxic technique for electrode positioning in the telencephalic nuclei of the Siamese Fighting fish (Betta splendens) is described. 2. The forebrain atlas was based on paraffin-embedded, in situ-sectioned, Nissl-stained material. Brain measurements were corrected for tissue shrinkage due to histological procedures. The atlas and methods have already been tested and have shown good accuracy and reproducibility.
Assuntos
Técnicas Estereotáxicas , Telencéfalo/anatomia & histologia , Animais , Peixes , Masculino , Técnicas Estereotáxicas/instrumentação , Telencéfalo/fisiologiaRESUMO
1. A stereotaxic technique for electrode positioning in the telencephalic nuclei of the Siamese Fighting fish (Beta splendens) is described. 2. The forebrain atlas was based on paraffin-embedded, in situ-sectioned, Nissl-stained material. Brain measurements were corrected for tissue shrinkage due to histological procedures. The atlas and methods have aledy been tested and have shown good accuracy and reproducibility
Assuntos
Animais , Técnicas Estereotáxicas , Telencéfalo/anatomia & histologia , Peixes , Telencéfalo/fisiologiaRESUMO
The effects of REM sleep deprivation (REMSD) for 96 h on discriminated avoidance learning were tested in rats using three different task topographies:in a jumping-box, in a shuttle-box and bar-pressing. The same stimulus relationship and the same methodological controls with regard to the avoidance schedules and to the platform technique were employed. REMSD facilitated the acquisition of the jumping-box response, which was detectable at the end of the third session. REMSD did not interfere in the acquisition of the shuttle-box response since both the experimental and control groups met the criterion by concluding the eighth session without any observable difference in the analyzed parameters. With bar-pressing, neither group reached the learning criterion (80% of avoidance responses throughout two consecutive sessions). We have related these results to the existing hypothesis that REM sleep stimulates the coding of all complex sequences of motor behavior which are necessary for innate behaviors and concluded that the reimbursement of the REM sleep debt after testing facilitated only the acquisition of the jumping-box response through a reprogramming of the motor organization of this innate behavior.
Assuntos
Aprendizagem da Esquiva/fisiologia , Aprendizagem por Discriminação/fisiologia , Privação do Sono , Sono REM , Animais , Feminino , Ratos , Ratos EndogâmicosAssuntos
Ratos , Animais , Feminino , Aprendizagem da Esquiva/fisiologia , Privação do Sono , Sono REMRESUMO
Stereotaxic electrolytic lesions were made in the dorsomedial telencephalic area, laterally to the dorsal commissure, in male Siamese Fighting Fish (Betta splendens). The startle and orienting responses to regularly delivered taps on the side of the aquarium were recorded for lesioned, sham-operated and unoperated groups. Lesioned fish showed increased reactivity to environmental modifications, including tonic immobility and changes in body color. Although no changes in the arousal responses were detected, the lesioned fish showed an increased frequency of startle responses and habituated to the orienting responses faster than sham-operated and unoperated animals. The long-term inter-session retention of habituation was also decreased. The effects observed are the opposite of those obtained after complete or unilateral telencephalic ablation in teleosts and suggest the existence of antagonic telencephalic systems playing a modulatory role in arousal control.
Assuntos
Nível de Alerta/fisiologia , Peixes/fisiologia , Habituação Psicofisiológica , Telencéfalo/fisiologia , Animais , Comportamento Animal , Encéfalo/patologia , Masculino , Técnicas EstereotáxicasRESUMO
The audiogenic crisis (AC) includes an initial phase of bursts of circular, stereotyped running. Since it has been shown that the nigrostriatal system is important in the control of lesion- and drug-induced stereotyped rotational behavior, the effects of unilateral electrolytic lesions of the substantia nigra (SN) on the AC were investigated. Behavior was recorded using a detailed ethogram by means of systematic observational techniques and analyzed quantitatively in terms of sequential structure by multivariate statistical methods. An index of susceptibility was computed on the basis of the frequency and intensity of the convulsive behavioral patterns observed during 4 successive pre- and post-operative tests. The lesion caused an increase in the susceptibility to AC of previously insusceptible rats or of low-susceptibility rats (LI), in relation to rats with sham lesions. No other differences of this type were detected for the groups of susceptible lesioned (LS) or non-lesioned animals. The sequential analysis disclosed a degradation in the tonic-clonic convulsive pattern of LS animals, with decreased frequency and more random transitions between their constituent units, as well as in the appearance of characteristic running patterns in LI rats. It is concluded that the SN plays a general inhibitory role in the central neural mechanisms of AC, and is involved in the integration and control of stereotyped local movements and of tonic-clonic convulsions. However, the SN might play only a secondary role in the control of the laterality and elaboration of the rotational phase.