Personality and affect characteristics of outpatients with depression.

This investigation was designed to examine the relationship between depression severity and personality disorders measured by the Millon Clinical Multiaxial Inventory-II (Millon, 1987) and affectivity measured by the Positive Affectivity/Negative Affectivity Schedule (Watson, Clark, & Tellegen, 1988). Discriminant analyses were employed to identify the personality and affective dimensions that maximally discriminate between 4 different levels of depressive severity. Differences between the 4 levels of depressive severity are suggestive of unique patterns of personality characteristics. Discriminant analysis showed that 74.8% of the cases were correctly classified by a single linear discriminant function, and that 61% of the variance in depression severity was accounted for by selected personality and affect variables. Results extend current conceptualizations of comorbidity and are discussed with respect to depression severity.

Early maladaptive schemas of personality disorder subtypes.

This investigation attempted to examine the cognitive schemas of five distinct clusters that emerged from a cluster analysis of the personality disorder scales of the Millon Clinical Multiaxial Inventory-II (Millon, 1987). Specifically, the degree to which early maladaptive schemas, as measured by the Cognitive Schema Questionnaire-Short Form (Young, 1994), could correctly identify empirically derived patterns of personality disorders was examined. Between-cluster differences centered on five personality components and five schemas. Discriminant analyses revealed two significant functions composed of cognitive schemas, which correctly identified 61.2% of the entire sample in terms of cluster group membership. The total proportion of variance in the two significant functions associated with cluster group differences was 76.8%. Findings are discussed in relation to the domain theory of personality disorders posited by Millon and Davis (1996).

A fractionator study of the effects of undernutrition during early life on rat Purkinje cell numbers (with a caveat on the use of nucleoli as counting units).

The effects of varying periods of general protein-calorie undernutrition during early life on Purkinje cells in the cerebellum of the rat were examined. In Experiment 1, animals were undernourished from d 18 of gestation until either d 30 or d 60 of postnatal age, followed in some cases by a period of nutritional rehabilitation. In Experiment 2, rats were undernourished from conception until d 30 postnatally, followed by a period of rehabilitation until 60 d of age. The 'fractionator' method was employed to estimate the total number of cerebellar Purkinje cell nucleoli. If each cell has one nucleolus, this number is equal to the number of Purkinje cells. In Experiment 1, the estimated mean number of Purkinje cell nucleoli varied between 188,000 and 273,000 for the groups of animals studied. However, the interanimal variation was large and 2-way analysis of variance tests failed to reveal any statistically significant age, nutrition or interaction effects. In Experiment 2, rats killed immediately after the period of undernutrition possessed significantly fewer Purkinje cell nucleoli than age-matched controls. This did not represent a real decrease in cell number. Instead, the result could be explained by a change of Purkinje cell morphology in undernourished rats. The change included nucleolar regression. Nutritionally rehabilitated animals had similar numbers of nucleoli to control rats. It is concluded that the levels and periods of undernutrition used in these experiments did not affect significantly the total numbers of cerebellar Purkinje neurons.

Effects of group membership on perception of risk for AIDS.

The role of social identity as a moderator for perception of risk for AIDS has not been examined. The purpose of this study was to examine perception of risk for AIDS as a function of membership in an identified risk group. 34 subjects who were homosexual, 58 intravenous drug users (IV), and 34 college students rated a 21-item list of behaviors for perception of AIDS risk. The findings indicate that the IV drug-use group significantly underestimated five risk behaviors, four of which are high probability behaviors of IV drug-users and two of which are exclusively IV drug-use behaviors. The homosexual group significantly underestimated four risk behaviors, all of which are primarily characteristic of that group. The college group was generally more accurate in assessing risk than either of the other two groups. These findings support the hypothesis that membership in a perceived risk group is related to differential perceptual bias associated with the need for positive social identity for one's group.

On the number of Purkinje cells in the human cerebellum: unbiased estimates obtained by using the "fractionator".

Stereological estimates of the numbers of Purkinje cell nucleoli in human cerebellar cortex have been obtained from systematic random samples of tissue by using the fractionator. The estimates are unbiased by fixation, section thickness, or sampling errors and are independent of any assumptions about cell shape, size, or spatial orientation. Twelve brains from aged subjects of both sexes were examined. The average complement of nucleoli in four female brains (age range 71-93 years) amounted to 14.8 millions (with an observed coefficient of variation between subjects of 29%). For three male brains (76-91 years), the corresponding estimates were 15.7 millions (10%). No significant sex differences were found for these small samples. Five brains of unknown sex and age yielded values of 15.8 millions (18%). For the twelve brains examined, the total number of Purkinje cell nucleoli per cerebellum was found to be 15.4 millions (19%). Estimated numbers showed a significant positive correlation with cerebellar weights. The number of nucleoli in an individual cerebellum was obtained with high precision in as short a time as 4 hours.

The effects of undernutrition during early life on spatial learning.

Recent research has shown that a lengthy period of undernutrition during early postnatal life can cause alterations in the morphological structure of the dentate gyrus. As this region is involved in the control of spatial memory, we decided to investigate whether undernourished rats also showed any deficits in this aspect of behaviour. Rats were undernourished from about birth until either 30 or 60 days of age and then nutritionally rehabilitated for a lengthy period before testing. There were significant differences in the body weight of control and undernourished rats in each experiment. The testing procedure involved rats being placed in a large pool of opaque water. They were required to swim to find a hidden platform located just below the water surface onto which they could escape. Each rat had to perform this test 20 times over a period of 3 days. The time taken and the total distance swum by each rat during each trial was measured. In Experiment 1, rats were familiarised with the water before testing took place, whereas in Experiment 2 they were not. There were no significant differences in the latency to find the platform or the distance swum between well-fed control and previously undernourished rats in either experiment. In conclusion, in our experiments we could not demonstrate that undernutrition during early life caused any deficits in spatial memory performance.