Behavior-driven arc expression is reduced in all ventral hippocampal subfields compared to CA1, CA3, and dentate gyrus in rat dorsal hippocampus.

Anatomical connectivity and lesion studies reveal distinct functional heterogeneity along the dorsal-ventral axis of the hippocampus. The immediate early gene Arc is known to be involved in neural plasticity and memory and can be used as a marker for cell activity that occurs, for example, when hippocampal place cells fire. We report here, that Arc is expressed in a greater proportion of cells in dorsal CA1, CA3, and dentate gyrus (DG), following spatial behavioral experiences compared to ventral hippocampal subregions (dorsal CA1 = 33%; ventral CA1 = 13%; dorsal CA3 = 23%; ventral CA3 = 8%; and dorsal DG = 2.5%; ventral DG = 1.2%). The technique used here to obtain estimates of numbers of behavior-driven cells across the dorsal-ventral axis, however, corresponds quite well with samples from available single unit recording studies. Several explanations for the two- to-threefold reduction in spatial behavior-driven cell activity in the ventral hippocampus can be offered. These include anatomical connectivity differences, differential gain of the self-motion signals that appear to alter the scale of place fields and the proportion of active cells, and possibly variations in the neuronal responses to non-spatial information within the hippocampus along its dorso-ventral axis.

GP job satisfaction in 1987, 1990 and 1998: lessons for the future?

BACKGROUND: Job satisfaction is an important determinant of physician retention and turnover, and may also affect performance. Objective. Our aim was to investigate changes in GP job satisfaction from 1987 to 1998, covering a period of major change in the organization of British general practice. METHODS: Postal surveys of random national samples of GPs were carried out by separate groups of investigators in 1987, 1990 and 1998. In each survey, the questionnaire contained a standardized job satisfaction scale and a list of 14 job stressors. The final samples consisted of 1817 GPs in 1987 (response rate 45%), 917 GPs in 1990 (response rate 61%) and 1828 GPs in 1998 (response rate 49%). RESULTS: For both men and women, overall job satisfaction declined from 1987 to 1990 and then improved from 1990 to 1998, although satisfaction in 1998 remained below that in 1987. Women tended to report higher levels of satisfaction than men in all 3 years. Satisfaction with nine specific aspects of work showed dissimilar patterns of change over time. From 1987 to 1990, reported levels of stress increased for eight of 14 job stressors. Of these, three subsequently declined in 1998, two remained unchanged and three continued to increase. Of the six job stressors which showed no change from 1987 to 1990, five subsequently increased as sources of stress. Men and women differed in their sources of stress, but the differences were not consistent over time. CONCLUSIONS: The results suggest that GP job satisfaction has improved significantly from the low point reached following the introduction of the 1990/1991 NHS reforms, although reported levels of stress in relation to many aspects of work have continued to increase. The changes are discussed within the context of wider research into the determinants of GP job satisfaction in order to anticipate the likely effects on GPs of future organizational reforms.

A comprehensive study of physical parameters, biomechanical properties, and statistical correlations of iliac crest bone wedges used in spinal fusion surgery. I. Physical parameters and their correlations.

Iliac crest bone wedges are commonly used in spinal fusion procedures and must be capable of withstanding considerable mechanical stress during the healing process. The variability of "quality" of bone materials used in the production of bone wedges suggests that some bone materials may not be suitable for use in vertebral fusion procedures and some quantifiable means of predicting the suitability of bone wedges would be desirable. A total of 250 iliac crest wedges were used in this study. Physical parameters of iliac crest wedges, such as total cross-sectional area, cancellous cross-sectional area, cortical cross-sectional area, percentage of cortical cross-sectional area, "width," and apparent density were determined. The statistical correlations among physical parameters were investigated. These correlations revealed that the relative percentage of cortical and cancellous bone remained fairly constant at 41% and 59%, respectively, regardless of total cross-sectional area of a wedge, that apparent density did not appreciably change with donor age, and that ash (inorganic) and organic content (weight) correlated well with the apparent density.

A comprehensive study of physical parameters, biomechanical properties, and statistical correlations of iliac crest bone wedges used in spinal fusion surgery. II. Mechanical properties and correlation with physical parameters.

Iliac crest wedges have been the most frequently used bone graft in spinal fusion procedures since the 1970s. Physical parameters and correlations among physical parameters of allogeneic iliac crest wedges have been described in part I of this series. This article discusses the mechanical properties, as well as their correlations with physical parameters, of iliac crest wedges. A total of 250 frozen-thawed, freeze-dried, and rehydrated iliac crest wedges were used in this study. The axial load-bearing capacities for wedges in the three subgroups showed no statistically significant differences, however, rehydrated wedges appeared to have the greatest load bearing capacity and compressive strength. In addition, rehydrated wedges were more deformable than either the frozen-thawed or freeze-dried wedges. Based on biomechanical properties, it is suggested that rehydrated (1 hour in vacuo), or frozen-thawed iliac crest wedge should be used in spinal fusion procedures, and the direct clinical application of nonrehydrated freeze-dried wedges should be avoided.

A comprehensive study of physical parameters, biomechanical properties, and statistical correlations of iliac crest bone wedges used in spinal fusion surgery. IV. Effect of gamma irradiation on mechanical and material properties.

The effects of gamma irradiation on mechanical and material properties of iliac crest wedges used in spinal fusion surgery were studied using uniaxial compression testing. The irradiated iliac crest wedges were exposed to 2-2.5 mrad as fresh-frozen and freeze-dried tissues. There were no significant differences in mechanical or material properties of the iliac crest wedges exposed to dosages of 2-2.5 mrad when compared to the nonirradiated wedges. It is suggested that 2-2.5 mrad is an acceptable dose for gamma irradiation sterilization of iliac crest wedges used in spinal fusion surgery and that these tissues may be treated at either the preprocessing or postprocessing stage of wedge production.

Identifying distress among general practitioners: predictors of psychological ill-health and job dissatisfaction.

This paper attempts to identify sources of job stress and personality factors as predictors of psychological ill-health and job dissatisfaction among a large sample of general practitioners in the United Kingdom. Compared to a normative sample, male doctors exhibit significantly higher levels of anxiety and depression, whereas female doctors compare favourably to the population norms. Job satisfaction levels were significantly lower than when they were measured in 1987, although women were less job dissatisfied than men. The main predictors of lack of mental well-being were the job stressors associated with the 'demands of the job and patients' expectations', 'practice administration and routine medical work', 'role stress' and the use of 'social support' as a coping strategy.

Job stress, satisfaction, and mental health among general practitioners before and after introduction of new contract.

OBJECTIVE: To compare measures of job stress, job satisfaction, and mental health among general practitioners before and after the introduction of the new contract in April 1990. DESIGN: Cross sectional postal questionnaire survey in July 1990. Comparison of results with those obtained in previous survey in November 1987. SETTING: General practice in United Kingdom. SUBJECTS: 1500 general practitioners randomly selected from general medical services lists, 917 of whom (61%) returned questionnaires usable for statistical analysis. MAIN OUTCOME MEASURES: Aspects of job causing stress, job satisfaction (Warr, Cook, and Wall scale), and mental health (Crown-Crisp experiential index). RESULTS: Compared with 1987, in 1990 doctors experienced more stress from night calls (mean score 3.83 in 1990 v 3.45 in 1987), emergencies during surgery hours (3.72 v 3.48), and interruption of family life by telephone (3.58 v 2.73; p less than 0.001 for all three variables). Scores for somatic anxiety and depression were higher in both men and women in 1990 (men: somatic anxiety 3.12 v 2.36; depression 3.80 v 2.94; women: somatic anxiety 3.56 v 2.65; depression 4.02 v 3.37; p less than 0.001). Job satisfaction had also decreased in 1990 (5.23 v 4.26; p less than 0.001). CONCLUSIONS: Doctors experienced more stress, less job satisfaction, and poorer mental health in 1990 than in 1987. These changes may have resulted from the introduction of the new contract.

Job stress, mental health, and accidents among offshore workers in the oil and gas extraction industries.

Psychosocial and occupational stressors among 194 male employees on drilling rig and production platform installations in the United Kingdom and Dutch sectors of the North Sea were studied. Mental well-being and job satisfaction were also assessed, with attention to the incidence of accidents offshore. This occupational group were found to be much less satisfied with their jobs than their onshore counterparts. Although overall mental well-being compared favorably with that of the general population, levels of anxiety were significantly higher. Multivariate analysis showed "relationships at work and at home" to be a strong predictor of both job dissatisfaction and mental ill-health. Type A coronary-prone behavior was also found to be a significant predictor of reduced mental well-being and increased accident rates offshore.

Regional distribution of barbital in the brain of mice during the development of tolerance and physical dependence.

ICR male mice each receiving a 16 mg barbital pellet implanted subcutaneously for three days developed about 40 percent tolerance to barbital and more than 50 percent tolerance to pentobarbital as measured by sleeping time. The development of physical dependence in these mice was demonstrated by an increased sensitivity to convulsions with pentylenetetrazol. The concentration of barbital rose to high levels in the subcortex and the cerebellum during the time between the implantation of the pellet and the loss of the righting reflex and distributed uniformly thereafter. After a challenge dose of the drug, higher barbital concentrations were found in these two areas as well as in the pons-medulla at 30 minutes and in all areas at the time of the loss of righting reflex, in withdrawn mice. The latter finding would indicate an increase in threshold for barbital anesthesia. The mechanisms of the higher uptake in the brain of withdrawn mice are discussed.