The toxicity of soluble metal compounds is often different from that of the parent metal. Since no reliable data on acute toxicity, local effects, and mutagenicity of beryllium metal have ever been generated, beryllium metal powder was tested according to the respective Organisation for Economical Co-Operation and Development (OECD) guidelines. Acute oral toxicity of beryllium metal was investi...

Continuous labelling of callus with H-thymidine results in intermittent peaks of H-DNA per chloroplast, showing synchrony of division. The increase in H-DNA could be due to several replication rounds, and the drop to successive plastid divisions without intervening DNA synthesis. The level of DNA-binding proteins in the chloroplast parallels the peaks of plastidal DNA synthesis; such pro...

UV micro-irradiation of a small part of the Chinese hamster nucleus and caffeine post-incubation often results in shattered chromosomes at the first post-irradiation mitosis. In some of these mitotic cells, chromosome shattering is restricted to a few chromosomes spatially related in a small area of the metaphase spread; in others, shattering includes the whole chromosome complement. These 2 ty...

The dynamic composition of proteins associated with nuclear DNA is a fundamental property of chromosome biology. In the chromatin compartment dedicated protein complexes govern the accurate synthesis and repair of the genomic information and define the state of DNA compaction in vital cellular processes such as chromosome segregation or transcription. Unscheduled or faulty association of protei...

OBJECTIVE To evaluate whether full-term deliveries resulting in neonates diagnosed with hypoxic-ischemic encephalopathy are associated with a significant increase in the rate of subsequent unscheduled cesarean deliveries. METHODS We conducted a retrospective chart review study and examined all deliveries in the Department of Obstetrics and Gynecology at Hadassah University Hospital, Mt. Scopu...

Objectives: To identify the reasons for unscheduled return visits to a public emergency department and possible strategies to reduce unscheduled return visits. Design: Cross-sectional survey. Setting: A public emergency department in Hong Kong. Patients: Unscheduled return visits within 48 hours in a threemonth period from 14 January 2000 to 15 April 2000. Main outcome measures: Patients' epide...

5,9-Dimethyldibenzo[c,g]carbazole (DMDBC), a potent mouse hepatocarcinogen, has been shown to induce a non-linear increase in mutant frequency in the liver of the transgenic MutaMouse. To gain insight into the mechanisms underlying the mutagenicity of DMDBC in vivo, DNA damage formation and removal were monitored in mouse hepatocytes over 4-144 h after a single skin application of 10 or 90 mg/k...

DNA repair is a system of defenses designed to protect the integrity of the genome. Deficiencies in this system likely lead to the development of cancer. The epidemiology of DNA repair capacity and of its effect on cancer susceptibility in humans is, therefore, an important area of investigation. We have summarized all of the published epidemiologic studies on DNA repair in human cancer through...

Methyleugenol (MEG), a constituent of human food, induces malignant tumors in multiple tissues of rats and mice. Although MEG forms DNA adducts and induces unscheduled DNA synthesis in rat liver, it is negative in many in vitro genetic toxicity assays. In the present study, we evaluated MEG-induced DNA damage in the rat using (1) the alkaline Comet assay, (2) the oxidative Comet assay, and (3) ...