Hamster cheek pouch carcinoma: effect of incision and cortisone on growth, invasion, and metastasis.

After cheek pouch carcinomas were induced in hamsters by the application of dimethylbenzanthracene (DMBA) to the right pouch for 13 weeks, the animals were divided into four groups and observed for seven more weeks. The control group received no further treatment, two experimental groups had incisional biopsies performed on tumors in their pouches, one of these also received injections of cortisone throughout the 20-week experimental period, and a fourth group received cortisone only. The wet weights of the cancerous cheek pouches were determined, and the submandibular and parotid salivary glands with associated cervical lymph nodes, the lungs, and the liver were examined with light microscopy.

Incisional biopsy and seeding in hamster cheek pouch carcinoma.

Surgical blades were contaminated by doing incisional biopsies on DMBA-induced cheek pouch carcinomas in hamsters. Contaminated blades were then used to: (1) make cytologic smears; (2) make incisions in the mucosal surface of the lower lip; (3) make incisions in the ventral surface of the tongue; (4) make incisions in the untreated left cheek pouch; and (5) make incisions in the pre-shaved back. One group of animals was killed three hr post-surgery.

Laboratory grouping based on previous courses.

In the human physiology course at Loyola University School of Dentistry, students (N = 761, second-year classes from 1971 to 1976) were divided into three laboratory groups according to prior experience with physiology courses and laboratories. To determine the effects of this grouping on academic performance, data were obtained on grades in the physiology course, National Board scores in physiology (combined with biochemistry from 1973 to 1976), predental GPA, and predental science GPA. Comparisons were made between the three groups using t-tests, and correlation coefficients were obtained for physiology grade and National Board score, predental GPA, and predental science GPA.

Temporary auditory threshold shift following sophomore operative technique laboratory.

Twenty sophomore dental students were studied for the "temporary threshold shift" (TTS) due to exposure to the noise of high-speed dental headpieces during technique laboratory sessions. TTS was experienced at all four frequencies tested--8000, 6000, 4000, and 3000 hertz, but tended to be greater and of longer duration at the higher frequencies. Approximately one-fourth of the students still had some hearing loss 15 minutes after leaving the laboratory.