OBJECTIVEThe aim of this study was to establish reference concentrations of urinary strontium by inductively coupled plasma atomic emission spectrometry (ICP-AES).

METHODSFor the determination of strontium, urine samples were collected from healthy Japanese (n=146; 115 males, 31 females; mean age, 33±9 years; age range, 18 to 58 years). The urine samples stored at or below -20°C were thawed with incubation at 40°C for 30 min and sediments were dissolved by vigorous shakings. Then, the samples were centrifuged at 3000 g for 5 min, and the supernatant was directly aspired into a P-5200-3600/1200 ICP-AES system from Hitachi Ltd., Tokyo, Japan.

RESULTSA steeper increase in the S/N ratio and a good effective linearity of the calibration line was obtained at 407.771 nm in the range of 0-300 μg/L strontium standard solution. Urine samples having the same background signal as that of 18 MΩ cm ultrapure blank water, a good correspondence of the single peak pattern of the spectra, accuracy and precision of spike recovery were also confirmed. Urinary strontium concentrations showed a log-normal distribution and a geometric mean concentration of 143.9 μg/L, with 5-95% confidential interval of 40.9-505.8 μg/L.

CONCLUSIONThe results of this study will be useful as guidelines for the biological monitoring of strontium in normal subjects and in individuals therapeutically or environmentally exposed to strontium.

Port site recurrence is a rare but well-documented adverse event peculiar to laparoscopic surgery. We report an unusual outcome of unexpected early stage ovarian cancer in which port site recurrence occurred after laparoscopic surgery and was followed by diffuse subcutaneous metastases. A 31-year-old Japanese woman with a large tumor in her abdomen visited our hospital. Because no intratumoral solid component was detected on diagnostic imaging, the tumor was diagnosed as a benign ovarian tumor and the patient underwent left ovarian laparoscopic cystectomy. Contrary to our expectations, however, the ovarian tumor was a mucinous carcinoma. We performed additional surgery, but the tumor recurred in the umbilical area, and multiple subcutaneous metastases later appeared. The curative effect of chemotherapy and radiation was limited. This atypical metastatic distribution of an extremely small amount of cancer might have been caused by the laparoscopic procedure. Protection against tumor cell dissemination is necessary during all forms of laparoscopic surgery.