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Biomedical subjects

S Telian

Publications and source records attributed to S Telian.

4 recordsLinked to original sources

Aggressive papillary middle ear tumors: a report of two cases with review of the literature.

Adenomatous tumors of the middle ear are rare, with only approximately 100 cases reported. A distinct subclass of this tumor demonstrates microscopic papillary architecture and has a propensity to erode the petrous bone and extend intracranially. The term "aggressive papillary middle ear tumor" has recently been proposed to describe this more invasive type of middle ear tumor. Thirty-seven cases of aggressive papillary middle ear tumors have been reported. We present two additional cases and discuss the clinical, radiologic, histologic, and operative features of this locally aggressive neoplasm. The tumor affects adults of both sexes. The clinical prodrome is prolonged. Presenting signs and symptoms most often relate to the involvement of cranial nerves V-VIII. Imaging studies reveal large, enhancing, destructive tumors with a generous vascular supply. Intraoperatively, the tumors are bloody, fibrous, and adherent to surrounding structures. Various surgical approaches in combination or in series may be used. Preoperative embolization may be helpful. The role of adjunctive radiation is unclear. Aggressive papillary middle ear tumors are histologically benign tumors with clinically destructive behavior. However, it appears that aggressive surgical management affords prolonged survival with minimal worsening of cranial nerve deficits.

Adenoma↗

Laryngeal brain stem evoked response in the porcine model.

Exaggeration of normally protective laryngeal reflexes is thought to play a role in several disorders, including the sudden infant death syndrome. An analysis of brain stem neural activity following laryngeal stimulation may provide insight into the pathophysiology of pathologic laryngeal reflexes and help to identify individuals at risk for these disorders. The purpose of this study was to define the far-field brain stem activity following laryngeal stimulation in the porcine model. This activity has been termed the laryngeal brain stem evoked response and may represent a potentially useful and objective measure of the neuronal activity in the laryngeal reflex pathway. Electrical stimulation of the superior laryngeal nerve was performed in 14 mixed-breed piglets under a variety of physiologic conditions. A total of six positive and six negative discrete waves were detected, with mean latencies ranging from 1.24 to 7.16 milliseconds. Stimulations performed during hypoxic, hypercapneic, or hypocapneic conditions resulted in no significant differences in waveform latencies. There appears to be a reproducible, but somewhat variable, brain stem response elicited by superior laryngeal nerve stimulation that can be recorded via a far-field technique in the porcine model.

Animals↗

Correlation between the laryngeal brain stem evoked response and the laryngeal chemoreflex in the porcine model.

The laryngeal brain stem evoked response (LBR) represents the neural activity involved in laryngeal reflex pathways. The laryngeal chemoreflex (LCR) is a centrally mediated response consisting of apnea and hemodynamic changes that result from laryngeal stimulation. The purpose of this study is to determine the characteristics of the LBR that are predictive of LCR severity in the porcine model. The duration of apnea resulting from stimulation of the supraglottic larynx defined LCR severity. The LBR tracings were recorded from electrodes flanking the brain stem following direct electrical stimulation of the superior laryngeal nerve. The LBR peak latencies from piglets demonstrating prolonged LCR apnea were compared to those without an exaggerated LCR response. Two LBR peak latencies demonstrated a statistically significant difference between the two piglet groups. These peak latencies appear to be indicators of susceptibility to exaggerated laryngeal reflex sensitivity. Thus, the LBR may prove useful in identifying and evaluating subjects predisposed to conditions associated with dysfunctional laryngeal reflex activity.

Animals↗