Nebraska experience.

Nebraska agencies and public health organizations collaboratively addressed cyanobacterial issues for the first time after two dogs died within hours of drinking water from a small private lake south of Omaha on May 4, 2004. A necropsy on one of the dogs revealed that the cause of death was due to ingestion of Microcystin toxins. Within two weeks after the dog deaths, state and local officials jointly developed strategies for monitoring cyanobacterial blooms and issuing public health alerts and advisories. Weekly sampling of public lakes for microcystin toxins and cyanobacteria was initiated during the week of May 17, 2004. ELISA laboratory equipment and supplies were purchased to achieve a quick turnaround time for measuring weekly lake samples for total microcystins so that public health advisories and alerts could be issued prior to each weekend's recreational activities. A conservative approach was selected to protect human health, pets, and livestock, which included collecting worst-case samples from cyanobacterial blooms; freezing and thawing of samples to lyse algal cells and release toxins prior to laboratory analysis; and using action levels of 15 ppb and 2 ppb of total microcystins, respectively, for issuing health alerts and health advisories. During 2004, five dog deaths, numerous wildlife and livestock deaths, and more than 50 accounts of human skin rashes, lesions, or gastrointestinal illnesses were reported at Nebraska lakes. Health alerts were issued for 26 lakes and health advisories for 69 lakes. Four lakes were on health alert for 12 or more weeks. The primary cyanobacterial bloom-forming genera identified in Nebraska lakes were Anabaena, Aphanizomenon, and Microcystis. Preliminary assessments of lake water quality data indicated that lower lake levels from the recent drought and low nitrogen to phosphorus ratios may have contributed, in part, to the increased numbers of cyanobacterial complaints and problems that occurred in 2004.

Granular cell tumor of the larynx in a six-year-old child: case report and review of the literature.

Granular cell tumors (granular cell myoblastomas) are uncommon neoplasms in the adult population, occurring predominantly in the head and neck and most frequently in the tongue. Laryngeal presentations are unusual, and granular cell tumors of the larynx in children are extremely rare, with a total of 19 cases reported in the literature in children under the age of 17 years. We report an additional case of a laryngeal granular cell tumor, in a six-year-old boy, and discuss the clinical, histologic, ultrastructural and therapeutic aspects of these neoplasms.

Film-screen sharpness in complex motion tomography.

An unsharp radiologic image is created in tomography by the combined motion of the x-ray tube and the film-screen cassette. This image is generally recorded at angles other than normal to the film-screen plane. A metbd for determining the influence of this recording angle on film-screen sharpness is described. The method involves imaging an edge target at various angles between the x-ray beam and the film-screen plane. The MTF is then calculated from the edge images. The effect of film-screen sharpness and quantum noise on subjective image quality in temporal bone tomography is discussed.