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Biomedical subjects

L Friberg

Publications and source records attributed to L Friberg.

134 records · Page 8Linked to original sources
PubMedDate not supplied

Accumulation of methylmercury and inorganic mercury in the brain.

Differences in metabolism between different mercury species are well recognized. Conclusions that only a minor demethylation of methylmercury takes place in the brain are based primarily on results from short term studies. Results from a number of studies on humans exposed for many years to methylmercury have shown high concentrations of inorganic mercury in the brain in relation to total mercury. Similar evidence is available from studies on monkeys exposed for several years to methylmercury. The results indicate that a significant accumulation of inorganic mercury takes place with time despite the fact that the demethylation rate is slow. Differences in biological halftimes between different mercury species will explain the results. Some data do still need confirmation using different analytical methods. There is reason to believe that the one-compartment model for methyl mercury cannot be used without reservations. Inorganic mercury has a complicated metabolism. After exposure to metallic mercury vapor, inorganic mercury, probably bound to selenium, accumulates in the brain. A fraction of the mercury is excreted, with a long biological halftime. Studies on rats and monkeys indicate that inorganic mercury penetrates the blood-brain barrier only to a very limited extent.

Animals↗
PubMedDate not supplied

Cadmium in kidney cortex, liver, and pancreas from Swedish autopsies. Estimation of biological half time in kidney cortex, considering calorie intake and smoking habits.

Cadmium and zinc have been analyzed in tissues from 292 persons autopsied in Stockholm. In kidney cortex, liver, and pancreas the individual cadmium levels are distributed in a lognormal way. In kidney cortex there is a continuous accumulation of cadmium with age up to 50 years, followed by a decrease. Smokers show a higher cadmium accumulation. For nonsmokers, the biological half time of cadmium in kidney cortex is estimated at 30 years, with an average concentration at age 50 of 11 mug/g wet weight. When smokers are included, the average cadmium concentration at age 50 is 22 mug/g wet weight. Based on the more pronounced cadmium accumulation among smokers than nonsmokers, the respiratory absorption rate of cadmium from tobacco smoke is estimated to be approximately 50%.

Adolescent↗
PubMedDate not supplied

Delayed reflow of an ischemic infarct after spontaneous thrombolysis studied by CBF tomography using SPECT and Tc-99m HMPAO.

A patient with a large ischemic infarct in the left middle cerebral artery territory was studied six times in the acute/subacute phase by cerebral blood flow (CBF) tomography using Tc-99m-HMPAO. The SPECT instrument used was a brain dedicated highly sensitive four-camera system (TOMOMATIC 232) that allows to keep the radioactivity dose per study at 10 mCi (370 MBq). Transcranial Doppler and angiography showed spontaneous disappearance of the middle cerebral artery occlusion between days 5 and 8, while CBF showed reperfusion of the borderzone with flow increasing over several days after resolution of the occlusion with flows reaching levels above that of the opposite non-affected side ("Luxury Perfusion"). The delayed reflow implies, that SPECT may not constitute a reliable tool for evaluating the success or failure of thrombolytic treatment in ischemic stroke.

Aged↗