Evaluation of the LKC stimulator for focal ERG testing.

Numerous studies have demonstrated the ability of focal ERGs to diagnose abnormally functioning maculae in the absence of funduscopic and angiographic signs, as well as to confirm diagnoses of clinically suspected macular disease. We present normative data on the second commercially available focal ERG stimulator (FCS-500, LKC Technologies), which may be added to the standard full field ERG systems currently used in many laboratories. The stimulator uses a monocular indirect ophthalmoscope to present a 5 degrees white stimulus flickering at 31.25 Hz in a 20 degrees background field. We have established a range of normal amplitudes (747-3000 nV) and implicit times (30.5-37.5 ms) for the instrument based on tests of 45 eyes of 45 normal patients. To confirm the validity of this test for diagnosis of ocular dysfunction we compared these normals to 46 eyes of 46 patients with macular disease and decreased acuity, and to 49 eyes of 49 patients with retinitis pigmentosa. Using Focal ERG amplitude alone, we found overall accuracy of 85% in diagnosing macular disease associated with decreased acuity. These findings confirm the validity and efficacy of the system we have evaluated.

Natural bites, food consistency and feeding behaviour in man.

Complete feeding sequences (bite to terminal swallow) were recorded in 11 individuals (Class I occlusions) feeding on apple, banana and biscuit (hard cookie) to establish whether jaw movements characteristic of the stage I transport, chewing, stage II transport and swallowing processes found in non-human mammals could be identified in man. All participants took large natural bites (known weight) of each food, but seven were supplied standard 6-g pieces of apple. Jaw movements (three axes) were recorded using a locally calibrated Sirognathograph. Discrete stage I transport movements (bite moved from incisors to postcanines), were found in most records, but least frequently for banana. The number of chewing cycles before the first in-sequence swallow increased in the order: banana, ( = ) apple without peel, apple with peel, biscuit. Chewing cycles showed subtle changes in gape profile but significant variation in mediolateral movement cycle to cycle. Morphologically distinct stage II transport cycles could not be identified. Swallows occurred intermittently during chewing (79% of all sequences, n = 146) with cycle durations in excess of 1 s in contrast to the range for chewing (0.6-0.7 s). Almost all sequences ended with a period, clearance, of highly irregular jaw movements often including swallows. Clearance has not been described in other mammals. Food consistency affected feeding behaviour. The "chew/swallow' ratio (total number of chews/total number of swallows) increased with food hardness. The number of chewing cycles before the first in-sequence swallow also increased. Food type significantly affected sequence duration. The duration of clearance was also affected by bite weight and food hardness. It is concluded that initial food consistency determines the number of chewing cycles before the first swallow and overall sequence duration. The change in the pattern of jaw movement in both the vertical and mediolateral directions cycle to cycle suggests continuous sensory modulation of the motor output to the mandibular musculature.

Evaluation of normal and abnormal hyoid bone movement during swallowing by use of ultrasound duplex-Doppler imaging.

We developed a new method to analyze normal and abnormal movements of the hyoid muscular region as an indicator of hyoid bone motion during swallowing using ultrasound duplex-Doppler imaging. Hyoid bone motion can be monitored by studying the Doppler shift spectra and B-mode images produced by ultrasound duplex imaging of the hyoid region muscular attachments. We can accurately determine swallowing duration and trajectory of hyoid bone movement. This procedure can assist in discriminating between normal and abnormal movements of the hyoid bone and the surrounding muscles during swallowing. This method appears to be a highly consistent measure. We suggest that Doppler spectrum analysis can be used for defining hyoid position and displaying accurate movement, which may be useful in the diagnosis of swallowing disorders.

Ensino aprendizagem. Relato de uma experiencia. / Apprenticeship-training Report of a experience

Apresentacao de um processo em ensino-aprendizagem desenvolvido num servico universitario durante tres anos uma populacao heterogenea de medicos e estudantes de medicina. Enfoque dos principais aspectos metodologicos tanto do ponto de vista estatico, de organizacao, como dinamico, de seu funcionamento. Visao critica do trabalho em grupo com a abertura de novas possibilidades na relacao medico-paciente

Intracerebroventricular administration of nanogram amounts of beta-endorphin and Met-enkephalin causes retrograde amnesia in rats.

The intracerebroventricular (icv) administration of 5.0 or 25.0 ng of beta-endorphin or Met-enkephalin causes retrograde amnesia for a shuttle avoidance task ion rats. In both cases, the higher dose was more effective than the lower one. The present results confirm previous similar findings obtained using systemic administrations of these compounds, and suggest that the amnestic effect of beta-endorphin and Met-enkephalin is mediated centrally.