A case of metastatic ameloblastoma of the maxilla with secondary hypercalcemia in a 54-year-old man is presented. After treatment with surgery, chemotherapy, and radiotherapy, the patient was found to have multiple metastases and severe hypercalcemia associated with high levels of parathormone-like substance in the peripheral blood. At autopsy he was found to have widespread metastases and nephrocalcinosis.

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Malignant melanoma of the ear, other than the pinna, rarely occurs. This is the first report of a melanoma confined to the external auditory canal. The case presented is of a 75-year-old man with a malignant melanoma confined to the external auditory canal. Excision of the tumor and surrounding lymphatics was accomplished with a lateral temporal bone resection, superficial parotidectomy, and selective neck dissection. The patient initially refused postoperative radiation therapy. Histologic evaluation documented a 17-mm thick malignant melanoma. All margins were clear and none of the nodes was positive. Eight months later, he returned with local, regional, and distant recurrence. Despite attempts at salvage with external radiation, brachytherapy, and chemotherapy, he died 13 months postoperatively with widespread disease. Melanoma confined to the external auditory canal has not been previously reported. A 17-mm thick melanoma carries a dismal prognosis. Despite initial negative surgical margins and lack of regional metastases, this patient developed a rapid, widespread pattern of recurrence.

SUMMARY The effect of temperature, time of storage, and presence of air bubbles in specimens for blood gas analysis was studied. The results show that air bubbles in a 10 % proportion are undesirable because of significant elevation in the Po2, and the storage of anaerobic blood samples at room temperature (250C) is acceptable when measurements are done within the first 20 minutes.The presence of air bubbles in blood samples for blood gas analysis can cause significant error in such determinations.' 2Although the potential of sucherror has been recognised, the clinical significance is not clear since most of the available data have been obtained from theoretical and experimental models.1-4 In this study we have analysed the observable effects of air bubbles introduced into blood samples and the time-temperature effects of storage. The results of the study show some of the actual effects of air bubbles and storage on routine blood gas determination. Material and methodsBlood samples were obtained from patients in the intensive care unit and coronary care unit of Milwaukee County Hospital by arterial puncture in a 6 ml disposable plastic syringe (Monoject (R)) containing a lead washer and approximately 0-2 ml of sodium heparin (1000 IU/ml). The volume of blood obtained was approximately 4-5 ml. Any entrapped air bubbles were removed immediately and the initial blood gas analysis was performed within 45 seconds using a Radiometer ABL-1 blood gas analyser. The syringes were sealed with a rubber cup and divided into three groups. In the first group an air bubble corresponding to 10% of the blood volume was introduced into the syringe, which was manually inverted 10 times and placed in ice (40C) for 15-20 minutes; then blood gases were measured. The second and third groups were kept anaerobically, one at 4VC and the other at room temperature (250C). Blood gases were determined at different intervals up to 120 minutes after the initial measurement. Comparative analysis of these results Received for publication 22 February 1980 was then performed based on the difference observed between the initial result and subsequent results from each sample. The statistical significance of differences was determined with a paired t test and the comparison of differences in the precision of the respective method was used for clinical appraisal of the various treatments.