False indication of arterial oxygen desaturation and methemoglobinemia following injection of methylene blue in urological surgery.

The pulse oximeter serves as an indicator of arterial oxygen saturation. We present two cases in which methylene blue injection during urological surgery appeared to cause arterial oxygen desaturation by pulse oximetry and methemoglobinemia by arterial blood gas co-oximetry. Methylene blue interferes with light absorption and gives a false estimate of the percentage of oxyhemoglobin and arterial oxygen saturation.

Cutaneous malignant mixed tumor.

Two cases of cutaneous malignant mixed tumor occurred in a 70-year-old man and a 69-year-old man. Nine previously described patients with cutaneous malignant mixed tumor resembled the two patients in this report, both clinically and histologically. All cases with adequate long-term follow-up evaluations were characterized by recurrence or metastasis.

Chronic methods to study the release of catecholamines from the neostriatum in nonanaesthetized monkeys (Macaca mulatta).

The present report describes two methods allowing the chronic collection of catecholamine (CA) released from the neostriatum in the nonanaesthetized monkey (Macaca mulatta). In both methods the monkeys were placed in a restraining chair. Indwelling electrodes allowed the correlation of behavioural observations with polygraphic recordings.