Biomedical subjects

G Santibañez

Publications and source records attributed to G Santibañez.

12 recordsLinked to original sources

PubMed1990

[Transmediastinal esophagectomy without thoracotomy in cancer of the esophagus].

Between 1987 and 1990 twenty report cases who suffered carcinoma of the esophagus underwent transmediastinal esophagectomy without thoracotomy at the Surgery Service of the Edgardo Rehabilitation Hospital. Of the report cases 90% were at stage III, 5% of stage II and 5% at stage I of the TNM Classification. Post operative complications were cervical leaks, transitory dysphonia and respiratory illness, and were solved by conservative management. Only one case died with sepsis and mediastinitis, this represents an inpatient mortality of 5%. There were no hemorrhagic complications, nor chylothorax neither visceral necrosis during surgical time. Transmediastinal esophagectomy offers a good choice for the management of surgical cases, it has low mortality, morbidity and similar survival time than other procedures.

Adult↗

PubMed1981

Effects of motor denervation of the external ear muscles on the audio-visual targeting reflex in cats.

The effect of uni- and bilateral denervation of muscles of the pinna on the audio-visual targeting reflex reinforced by food was studied. In comparison with the normal group the unilaterally denervated animals showed a decreased capacity to localize sound sources placed behind the animal ipsi- and contralaterally to the operated side. The denervation of the second ear in these animals induced a further decrease of the localization scores, especially of the sources placed behind them. The localization behavior strategies were different depending on the integrity of the innervation of muscles of the pinna. The stimulation of the operated side with tones of a 30 dB higher intensity than in the normal side did not improve the animalsperformance in localizing the sound sources. The shortening of duration from 500 to 50 ms reduced, the capacity to localize the loudspeakers placed ipsilaterally to the denervated side, especially those behind the animal. The role for the targeting reflex of the feedback information from the muscles controlling the pinna movements, and the significance of the postural changes induced by the tone are discussed.

Animals↗

PubMed1979

Conditioned audio-visual targeting reflexes in split brain cats.

A conditioned audio-visual targeting reflex was elaborated in 12 freely moving cats. The cats had to localize the loudspeaker emitting by a tone of 1600 Hz, of 500 ms duration and 80 dB intensity. Each time one of the eight loudspeakers placed in front and behind the cat was activated and the targeting reaction rewarded by food. Normal cats attained the 80 percent criterion for the front and rear loudspeakers in 20 and 30 sessions, respectively. The influence of the transection of the corpus callosum on acquisition and retention of the targeting reaction was investigated. The split brain animals with pre-operative experience in the situation did not show any retention, but relearned the targeting of the frontal sources in 20 sessions. No relearning of the posterior sound sources was observed. The animals that had only post-operative training did not reach 80 percent of correct responses in 50 sessions. Corpus callosum transection influences the integration of the targeting reaction in different ways, depending on the position of the sound source and on pre-operative training.

Animals↗

PubMed1974

Macroelectrodic activity of the facial nucleus of the cat.

Bipolar stainless steel electrodes were implanted in the facial nucleus. Animals were stimulated with clicks, flashes and electric discharges applied over several points of the skin. The interaction among these modalities was presented before or after electrical stimulation of the cortex. All these stimuli produced evoked potentials in the facial nucleus. These were characterized by a biphasic potential of short latency (5 ms) and small amplitude (20-40 microvolts), followed by a negative monophasic deflection (latency of 35-40 ms and amplitude of 150-250 microvolts). This responses varied partially depending upon the modality of stimulation and the position of the facial nucleus electrode. Precollicular transection and ablation of the sigmoidean gyrus resulted in a marked reduction of the negative wave; while the initial deflection was not affected. It is concluded that the facial nucleus plays a role in the auditory localization and orienting reactions of the animal.

Animals↗

PubMed1971