Transformation of immortal, non-tumorigenic osteoblast-like human osteosarcoma cells to the tumorigenic phenotype by nickel sulfate

Epidemiological studies have indirectly linked compounds ofchromium, nickel and arsenic to human carcinogenesis. However,there is no evidence that metal compounds can transform humancells to the tumorigenic phenotype in culture. We show herethat exposure to 36 µM NiS0₄ for 48–96 h resultsin transformation of an immortal, non-tumorigenic, osteoblast-likecell line, HOS TE85, to the tumorigenic phenotype. Continuouspassaging following treatment leads to the formation of a fewdense foci. The cells isolated and expanded from the foci aremorphologically transformed, and form anchorage-independentcolonies of the size and abundance comparable to that formedby Kirsten murine sarcoma virus transformed HOS TE85 cells.The transformed cells from tumors in nude mice, have enhancedlevels of plasminogen activators and have lost the ability toform model bone matrix on extended culture in the presence ofascorbic acid and ß-glycerophosphate. A number ofcell lines have been established from nude mouse tumors. Cytogeneticanalysis reveals 16 marker chromosomes and an aberrant chromosome16. This is the first report of the transformation of a humancell line to tumorigenic phenotype by a metal carcinogen.     

A critical appraisal of the anaesthesia literature

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - Today’s anaesthesia journals are faced with problems in the quality of materials being published. The stature of...     

Primary carcinoid tumor of the urinary bladder.

A 62-year-old woman who presented with urinary frequency and microscopic hematuria was found to have a 1.2 x 1.0 x 0.6-cm polypoid carcinoid tumor of the urinary bladder. The tissue resected from the base after removal of the polypoid lesion disclosed a small focus of residual carcinoid tumor, associated with Brunn's epithelial nests, cystitis cystica, and cystitis glandularis. Tumor cells exhibited strong argyrophilia and weak argentaffinity. Immunohistochemical staining reactions were strongly positive for chromogranin and serotonin, and electron microscopy revealed characteristic dense-core granules. Flow cytometric evaluation revealed an aneuploid cell population with a DNA index of 1.20.     

Child abuse by burning--an index of suspicion

Although general awareness of child abuse is increasing, abuse by burning is often unrecognized. Seventy-one consecutive children admitted with inflicted burns were studied. Mean age was 1.8 yrs and mean burn size was 13.5%. Mean length of stay was 18.9 days. Scalds (83% from tap water) were the most frequent cause of injury. An immersion pattern was present in 59%; six patients had a classic forced immersion injury. Fourteen children had nonburn trauma. Four patients died: all had tap water immersion burns. Inflicted burns are usually manifested by characteristic patterns of injury, which must be correlated with the given history. When compared with accidentally burned children, abused children were significantly younger, had longer hospital stays, and had a higher mortality. A team approach to child abuse with the addition of a specially trained group is important to insure prompt recognition, more objective appraisals, and further followup.     

Reward summation and the effects of pimozide, clonidine, and amphetamine on fixed-interval responding for brain stimulation.

Two models of reward summation were examined in 16 rats lever pressing for intracranial stimulation under fixed-interval (FI) reinforcement. The first model examined rate-frequency functions and the second model traded off frequency and train duration. The second model was selected to assess the effects of three drugs on reward summation. Both clonidine and pimozide inhibited FI self-stimulation, but pimozide's effect could not be distinguished from a performance deficit. Two amphetamine isomers facilitated self-stimulation in a manner suggesting enhanced reinforcement. The dextro isomer was four times more effective than the levo isomer to facilitate self-stimulation. This study shows that the combination of the FI schedule with a reward-summation model is well suited for evaluating the effects of drugs on self-stimulation. The advantages of this model are that inter-reinforcement intervals are separated, which minimizes priming and stimulation aftereffects, and more responding does not increase stimulation availability, thus eliminating rate-dependency effects.