Background: The main forms of mercury (Hg) exposure in the general population are methylmercury (MeHg) from seafood, inorganic mercury (I-Hg) from food, and mercury vapor (Hg 0 ) from dental amalgam restorations. While the distribution of MeHg in the body is described by a one compartment model, the distribution of I-Hg after exposure to elemental mercury is more complex, and there is no biomarker for I-Hg in the brain. The aim of this study was to elucidate the relationships between on the one hand MeHg and I-Hg in human brain and other tissues, including blood, and on the other Hg exposure via dental amalgam in a fish-eating population. In addition, the use of blood and toenails as biological indicator media for inorganic and organic mercury (MeHg) in the tissues was evaluated.

After radical surgery for rectal adenocarcinoma, the presence of venous and neural invasion of tumor cells was correlated with the pattern of treatment failure, local in the pelvis or distant. Of 128 operation specimens, venous and neural invasion was demonstrated in 22 percent and 32 percent, respectively. A significant decrease of the distant recurrence-free 5-year survival (Kaplan-Meier method) was seen when venous invasion was demonstrated (32.9 percent vs. 84.3 percent; P less than 0.0001), whereas more local failures were registered in patients with neural invasion. The local recurrence-free 5-year survival in patients with neural invasion was 64.3 percent, compared with 81.1 percent when neural invasion was not demonstrated (P = 0.03). Their prognostic value was then studied in a Cox regression model including stage and grade. Neural invasion had the strongest association with local recurrences, whereas venous invasion was found to be the third strongest independent predictor of metastasis, after lymph node status and extent of local tumor infiltration. We conclude that examining for the presence of venous and neural invasion gives reliable prediction of recurrences after radical resection of rectal cancer. Recording of tumor recurrence pattern may lead to a better selection of patients for adjuvant therapy after surgery.

The proportion of prone sleeping among sudden infant death syndrome (SIDS) victims and infants in general, and the rate of SIDS were prospectively studied in the county of Hordaland, Norway, three years before (1987-89) and three years after (1990-92) a campaign to discourage prone sleeping. Before the campaign, 64% of random reference infants were put prone versus 8% after (p < 0.0001). Concurrently, the rate of SIDS decreased from 3.5 to 1.6 per 1000 live births (63 infants before and 30 after the campaign, p = 0.0002). Prone sleeping was not considered a statistically significant risk factor for SIDS before (OR 2.0, 95% CI 0.8-4.5), but was highly significant (OR 11.3, 95% CI 3.6-36.5) after the campaign. Prone sleeping is an important risk factor for SIDS, but the association may be missed in epidemiological studies if prone is the predominant sleeping position. Behaviour with regard to sleeping position may be changed rapidly by means of a simple campaign.

A randomized, multicenter clinical trial was conducted in Western Norway to study the effectiveness of preoperative radiation therapy in operable rectal cancer, given at a dosage of 3150 cGy in 18 fractions, 2 to 3 weeks before radical surgery. Three hundred nine patients were entered into the trial between May 1976 and December 1985. After radiation no tumor was seen in 4.5% of the patients. There was no increased morbidity or mortality at surgery. The 5-year survival for evaluable patients was 57.5% in the control group and 56.7% in the radiotherapy group. For patients operated on for cure the 5-year survival was 60.9% and 64.2% in the control group and radiotherapy group, respectively. Radiation significantly delayed both local and distant recurrences in patients in the radiation group who had curative resection from 13.3 months in controls to 27.1 months. The local recurrence rate in the corresponding groups was 21.1% and 13.7%, respectively. We conclude that higher preoperative radiation doses should be used in new trials as a higher dosage may transform the observed positive effects into a survival benefit.