Hemimaxillectomy was performed in 69 dogs for the treatment of benign or malignant maxillary tumors. Eighteen dogs with ameloblastomas had a median disease-free interval of 21.5 months (range, 1 to 76 months), with a 72% 1-year survival time. There was recurrence in three dogs, with metastasis after malignant transformation in one of them. Based on calculated survival curves, seven dogs with squamous cell carcinoma had a median survival time of 19.2 months (range, 2 to 24 months), with a 57% 1-year survival time. There was local recurrence in two dogs. Twenty-three dogs with melanoma had a median survival time of 9.1 months (range, 1 to 46 months), and a 27% 1-year survival time. Twelve dogs died or were euthanatized because of recurrence or metastases. Fifteen dogs with fibrosarcoma had a median survival time of 12.2 months. Eight dogs died or were euthanatized because of recurrence or metastases. Six dogs with osteosarcoma had a median survival time of 4.6 months (range, 1 to 12.5 months), with a 17% 1-year survival time. Five dogs died or were euthanatized for recurrence or metastases. Tumor size or location and type of partial maxillectomy performed did not affect survival.

Four age groups of Fischer 344 rats (6-, 12-, 18-, and 24-months of age) were compared on a battery of reflexive and locomotor tasks. The simple reflexive tasks such as placing, hopping, negative geotaxis and surface and mid-air righting showed little or no change as a function of age. In contrast, tasks requiring more coordinated control of motor and reflexive responses such as suspension from a horizontal wire, descent of a wire mesh pole, traversal of an elevated platform and rotorod performance showed significant declines with age, with some declines noticeable early in the lifespan. When these results are compared with the results of tasks conducted with infant rats, it is noted that the reflexive and motor skills that emerge early in development are the least affected by the aging process. This observation suggests a first-in, last-out sequence for reflexive and motor behaviors.

Short-term and spatial memory were studied in Fischer 344 rats ranging in age from 6 to 26 months of age. Spatial memory, as measured by performance in an 8-armed radial maze, declined gradually with age. In contrast, short-term memory, as measured by retention of previous choices in the spatial maze over short intervals and performance on a modified form of Konorski's discriminated delayed response task, did not decline differentially as a function of age. These findings may be comparable to those obtained in the aged human, who also show marked deficits in spatial memory and little change in primary memory under appropriate test conditions.

Depressive symptomatology was examined in a large sample of noninstitutionalized older adults using the Center for Epidemiological Studies-Depression scale (CES-D). Both cross-sectional and longitudinal data showed age-related increases in mean CES-D scores and increases in the percentage of respondents scoring at or above the cutoff score of 16. Variables collected at baseline in the longitudinal study from 2,032 participants 65 years of age and older were significant predictors of depressive symptomatology 3 and 6 years later. Baseline CES-D scores accounted for the largest proportion of the variance.

Two experimental paradigms are presented aimed at determining the retention of auditory and visual information over brief delay intervals. First, a conditional delayed matching-tosample procedure was used in which rats were required to symbolically match the modality of the sample stimulus with one of two comparison stimuli. In the second experiment, subjects were trained and tested using a Konorski-type procedure. Despite the conceptual and procedural differences between the two procedures, subjects in both experiments showed steeper forgetting functions for visual events than for auditory events, while performance levels at O-sec delay intervals were equivalent for both stimuli. These results, when taken together with related research conducted with pigeons, suggest that content of memory may have important influenceson the short-term retention abilities of animal subjects.Surprisingly little is known about forgetting of recent events in the laboratory rat. Although Hunter (1913) reported that rats could retain the spatial location of visual stimulus representing food for a maximumof 10 sec, successful performance appeared to be dependent upon the use of response-directing behaviors which mediated the delay. More recent investigators have modified Hunter's procedure and have studied short-term retention using delayed response and delayed alternation tasks (e.g., Gordon, Brennan, & Schlesinger, 1976;Roberts, 1974). These paradigms have been problematic, however, primarily because they do not allow for precise experimental specification of the event the rat is required to retain. While the delayed matching-to-sample (DMTS) task has proven to be a useful method for measuring