Individual and community experiences of posttraumatic growth after disaster: 10 years after the Australian Black Saturday bushfires

OBJECTIVE

To understand longer-term posttraumatic growth (PTG) and how this is associated with individual and community bushfire experiences.

METHOD

Survey data (n = 391) from the Beyond Bushfires and the 10-year Beyond Bushfires studies were analyzed. Multilevel modeling examined relationships between basic individual demographics, bushfire exposure, and community-level variables at 3-4 years after the fires, and PTG at 10 years using the short form of the PTG Inventory.

RESULTS

Ten years after these Australian bushfires, being female, experiencing higher degrees of property loss, and stronger individual sense of community were the factors associated with PTG. Approximately 12% of the variance observed in PTG scores was attributable to differences in PTG across communities. Individuals from medium and high bushfire-affected communities reported significantly higher PTG relative to those in low bushfire-affected communities. While there was evidence of community differences in PTG, and individuals' own sense of community was positively and significantly associated with increased PTG, community-level cohesion scores were not found to be significantly related to PTG (although the trend was in the expected direction).

CONCLUSIONS

PTG is evident in longer-term disaster recovery. While PTG appears to vary across communities, the findings suggest that it is an individual's own sense of community (rather than community-level cohesion) that is most closely related to this longer-term growth following a bushfire event. While PTG is currently understood as an outcome of individual-level perceptions, community-level experiences shape the potential for positive transformations to occur after disasters and warrant further investigation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

School staff wellbeing: A network-based assessment of burnout

Burnout is commonly associated with professions that entail a high rate of close relationships with other individuals or groups. This paper explores the association between burnout and interpersonal relationships using a relational, social network framework. We collected data on advice-seeking relationships among 102 teachers and administrative staff from a secondary school in Melbourne, Australia. Burnout was measured using the Burnout Assessment Tool and we focused on four core subscales: (1) exhaustion; (2) mental distance; (3) emotional impairment; and (4) cognitive impairment. We applied a particular class of statistical model for social networks called Exponential Random Graph Models (ERGMs) to shed new light on how level of burnout relates to formation of advice relations among school staff. Results indicated that high levels of overall burnout were linked to a higher number of advice-seeking ties among school staff. Additionally, teachers who scored high in cognitive impairment (i.e., difficulties in thinking clearly and learn new things at work) tended to seek and to provide advice to a greater number of others. Finally, school staff who scored high in exhaustion (i.e., a severe loss of energy that results in feelings of both physical and mental exhaustion) tended to be sought out less as advisors to others, while those high in mental distance (i.e., psychologically distancing oneself from others) were generally less likely to seek advice from other school staff. We discuss these findings drawing on Conservation of Resource theory. Notably, our results show that burnout is not only an individual-level problem, but that burnout is associated with reduced social connectivity in specific ways that may impact on how other school staff collaborate, culminating in a staff-wide overall impact that affects how schools function.

The dynamic course of psychological outcomes following the Victorian Black Saturday bushfires

OBJECTIVES

To profile the long-term mental health outcomes of those affected by the 2009 Black Saturday bushfires and to document the course of mental health since the disaster.

METHOD

The longitudinal Beyond Bushfires study included 1017 respondents (Wave 1; 3-4 years after the fires), 736 (76.1%) at Wave 2 (5 years after the fires) and 525 (51.6%) at Wave 3 (10 years after the fires). The survey indexed fire-related and subsequent stressful events, probable posttraumatic stress disorder, major depressive disorder, alcohol use, severe distress and receipt of health services for mental health problems.

RESULTS

Relative to their status 3-4 years after the fires, there were reduced rates of fire-related posttraumatic stress disorder (6.2% vs 12.2%), general posttraumatic stress disorder (14.9% vs 18.7%) and severe distress (4.4% vs 7.5%) at 10 years. There were comparable rates between Wave 1 and Wave 3 for depression (10.9% vs 8.3%) and alcohol abuse (21.8% vs 18.5%). Of people in high-affected regions, 22.1% had posttraumatic stress disorder, depression or severe distress at Wave 3. One-third to one-half of participants who reported probable posttraumatic stress disorder or depression at any assessment did not display the disorder at the next assessment. Worsening of mental health at Wave 3 was associated with the extent of property loss, exposure to recent traumatic events or recent stressful life events. Only 24.6% of those with a probable disorder had sought professional help for this in the previous 6 months.

CONCLUSION

Approximately one-fifth of people from high-affected areas have a probable psychological disorder a decade after the fires. Mental health appears to fluctuate for those who are not consistently resilient, apparently as a result of ongoing stressors. The observation that most people with probable disorder are not receiving care highlights the need for further planning about managing long-term mental health needs of disaster-affected communities.

Anger Dimensions and Mental Health Following a Disaster: Distribution and Implications After a Major Bushfire

Anger is an important dimension of affect and a prominent feature of posttraumatic mental health, but it is commonly overlooked in postdisaster settings. We aimed to examine the distribution and implications of significant anger problems in the aftermath of a natural disaster, via analyses of Beyond Bushfires survey data from 736 residents of rural communities 5 years after the 2009 Black Saturday bushfires in Victoria, Australia. Assessments included the five-item Dimensions of Anger Reaction (DAR-5) scale along with measures of PTSD, depression, and significant mental illness, and indicators of life satisfaction, suicidality, hostile aggressive behavior, and violence exposure. The results indicated that approximately 10% of respondents from areas highly affected by the bushfires scored above the provisional cutoff criteria for significant anger problems on the DAR-5, which was a more than 3-fold increase, OR = 3.26, relative to respondents from areas of low-to-moderate bushfire impact. The rates were higher among women, younger participants, and those who were unemployed, and co-occurred commonly, although not exclusively, with other postdisaster mental health problems. Anger problems were also associated with lower life satisfaction, β = -.31, an 8-fold increase in suicidal ideation, OR = 8.68, and a nearly 13-fold increase in hostile aggressive behavior, OR = 12.98. There were associations with anger problems and violence exposure, which were reduced when controlling for covariates, including probable PTSD. The findings provide evidence indicating that anger is a significant issue for postdisaster mental health and should be considered routinely alongside other posttraumatic mental health issues.

Interpersonal violence and mental health outcomes following disaster

BACKGROUND

Disasters pose a documented risk to mental health, with a range of peri- and post-disaster factors (both pre-existing and disaster-precipitated) linked to adverse outcomes. Among these, increasing empirical attention is being paid to the relation between disasters and violence.

AIMS

This study examined self-reported experiences of assault or violence victimisation among communities affected by high, medium, and low disaster severity following the 2009 bushfires in Victoria, Australia. The association between violence, mental health outcomes and alcohol misuse was also investigated.

METHOD

Participants were 1016 adults from high-, medium- and low-affected communities, 3-4 years after an Australian bushfire disaster. Rates of reported violence were compared by areas of bushfire-affectedness. Logistic regression models were applied separately to men and women to assess the experience of violence in predicting general and fire-related post-traumatic stress disorder, depression and alcohol misuse.

RESULTS

Reports of experiencing violence were significantly higher among high bushfire-affected compared with low bushfire-affected regions. Analyses indicated the significant relationship between disaster-affectedness and violence was observed for women only, with rates of 1.0, 0 and 7.4% in low, medium and high bushfire-affected areas, respectively. Among women living in high bushfire-affected areas, negative change to income was associated with an increased likelihood of experiencing violence (odds ratio, 4.68). For women, post-disaster violence was associated with more severe post-traumatic stress disorder and depression symptoms.

CONCLUSIONS

Women residing within high bushfire-affected communities experienced the highest levels of violence. These post-disaster experiences of violence are associated with post-disaster changes to income and with post-traumatic stress disorder and depression symptoms among women. These findings have critical implications for the assessment of, and interventions for, women experiencing or at risk of violence post-disaster.

Delayed Disaster Impacts on Academic Performance of Primary School Children

Social disruption caused by natural disasters often interrupts educational opportunities for children. However, little is known about children's learning in the following years. This study examined change in academic scores for children variably exposed to a major bushfire in Australia. Comparisons were made between children attending high, medium, and low disaster-affected primary schools 2-4 years after the disaster (n = 24,642; 9-12 years). The results showed that in reading and numeracy expected gains from Year 3 to Year 5 scores were reduced in schools with higher levels of bushfire impact. The findings highlight the extended period of academic impact and identify important opportunities for intervention in the education system to enable children to achieve their academic potential.

The effect of group involvement on post-disaster mental health: A longitudinal multilevel analysis

Involvement in voluntary associations is a key form of social capital and plays an especially important role following disaster as a venue for coordination and decision-making for the wider community. Yet, relatively little attention has been paid to how group involvement affects mental health, at either the individual or community level. The aim of this study was to assess the impact of involvement in voluntary associations on mental health among residents of bushfire-affected communities. A longitudinal sample of 642 individuals affected by the 2009 Victorian bushfires in south-eastern Australia were surveyed in 2012 and 2014 (3- and 5-years post-disaster). A further subsample (n = 552) of residents residing continuously within 22 bushfire-affected communities were examined for community-level effects using multilevel regression methods. After adjusting for demographics, disaster exposure, and network variables, group involvement at time 1 bore a curvilinear relationship with PTSD at both time points: moderate involvement was most beneficial, with no participation, or high amounts, yielding poorer outcomes. High amounts of group involvement was likewise linked to a greater risk of major depression. Furthermore, communities with higher median levels of group involvement reported lower levels of PTSD symptoms and major depression two years later. With respect to group involvement, more is not always better. For individuals, moderation - if possible - is key. Meanwhile, community-level health benefits come when most people participate to some extent, suggesting that the distribution of involvement across the community is important.

Dyadic effects of attachment on mental health: Couples in a postdisaster context

Research on mental health following disasters has led to the identification of many individual protective and risk factors for postdisaster mental health. However, there is little understanding of the exact influence that disasters have on the functioning of intimate relationships. Especially relevant are attachment styles, which are likely to play an important role in the provision and perception of social support between partners, and subsequent mental health outcomes. Heterosexual couples (N = 127) affected by the 2009 Victorian "Black Saturday" Bushfires in southeastern Australia were surveyed for disaster experiences, posttraumatic stress disorder (PTSD) symptoms, depression, and attachment style between May 2012 and January 2013, approximately 3 years after the disaster. Using actor-partner interdependence models (APIM), we examined both intrapersonal and interpersonal associations of attachment anxiety and avoidance with depression and PTSD, in combination with shared disaster exposure. Male partners' attachment avoidance was associated with depression and PTSD in both partners. By contrast, a female partner's attachment avoidance was associated with greater depression and PTSD in herself, but fewer PTSD symptoms in a male partner. Amid the chronic stressors of a postdisaster setting, the attachment avoidance of the male partner may play a particularly negative role, with his tendency toward isolation and denial becoming especially maladaptive for the couple as a whole. The female partner's attachment avoidance is likewise an important factor, but its associations with negative social support and relationship breakup must be clarified to understand its impact on partnership functioning. (PsycINFO Database Record

Mental Health and Social Networks After Disaster

OBJECTIVE

Although disasters are a major cause of mental health problems and typically affect large numbers of people and communities, little is known about how social structures affect mental health after a disaster. The authors assessed the extent to which mental health outcomes after disaster are associated with social network structures.

METHOD

In a community-based cohort study of survivors of a major bushfire disaster, participants (N=558) were assessed for probable posttraumatic stress disorder (PTSD) and probable depression. Social networks were assessed by asking participants to nominate people with whom they felt personally close. These nominations were used to construct a social network map that showed each participant's ties to other participants they nominated and also to other participants who nominated them. This map was then analyzed for prevailing patterns of mental health outcomes.

RESULTS

Depression risk was higher for participants who reported fewer social connections, were connected to other depressed people, or were connected to people who had left their community. PTSD risk was higher if fewer people reported being connected with the participant, if those who felt close to the participant had higher levels of property loss, or if the participant was linked to others who were themselves not interconnected. Interestingly, being connected to other people who in turn were reciprocally close to each other was associated with a lower risk of PTSD.

CONCLUSIONS

These findings provide the first evidence of disorder-specific patterns in relation to one's social connections after disaster. Depression appears to co-occur in linked individuals, whereas PTSD risk is increased with social fragmentation. These patterns underscore the need to adopt a sociocentric perspective of postdisaster mental health in order to better understand the potential for societal interventions in the wake of disaster.

Mental Health Following Separation in a Disaster: The Role of Attachment

Short-term separation from close family members during a disaster is a highly salient event for those involved. Yet, its subsequent impact on mental health has received little empirical attention. One relevant factor may be attachment style, which influences patterns of support-seeking under threatening conditions. Individuals (N = 914) affected by the 2009 Victorian bushfires in southeastern Australia were assessed for disaster experiences, depression, posttraumatic stress disorder (PTSD) symptoms, and attachment style 3-4 years after the fires. Using multigroup structural equation modelling, individuals who reported separation from close family members during the bushfires (n = 471) were compared to those who reported no separation (n = 443). Cross-sectional results indicated that separated individuals had higher levels of PTSD symptoms. Furthermore, attachment anxiety was more strongly positively associated with depression among separated (b = 0.62) versus not separated individuals (b = 0.32). Unexpectedly, among separated individuals, attachment avoidance had a statistically weaker association with depression (b = 0.17 vs. b = 0.35) and with PTSD symptoms (b = 0.06 vs. b = 0.22). These results suggest that attachment anxiety amplifies a negative reaction to separation; meanwhile, for avoidant individuals, separation in times of danger may facilitate defensive cognitive processes.

Psychological outcomes following the Victorian Black Saturday bushfires

OBJECTIVE

We aimed to map the prevalence and predictors of psychological outcomes in affected communities 3-4 years after the Black Saturday bushfires in the state of Victoria, Australia.

METHODS

Baseline assessment of a longitudinal cohort study in high-, medium-, and low-affected communities in Victoria. Participants included 1017 residents of high-, medium-, and low-affected fire communities. Participants were surveyed by means of a telephone and web-based interview between December 2011 and January 2013. The survey included measures of fire-related post-traumatic stress disorder (PTSD) and general PTSD from other traumatic events, major depressive episode, alcohol use, and general psychological distress.

RESULTS

The majority of respondents in the high- (77.3%), medium- (81.3%), and low-affected (84.9%) communities reported no psychological distress on the K6 screening scale. More participants in the high-affected communities (15.6%) reported probable PTSD linked to the bushfires than medium- (7.2%) and low-affected (1.0%) communities (odds ratio (OR): 4.57, 95% confidence interval (CI): 2.61-8.00, p = 0.000). Similar patterns were observed for depression (12.9%, 8.8%, 6.3%, respectively) (OR: 1.83, 95% CI: 1.17-2.85, p = 0.008) and severe psychological distress (9.8%, 5.0%, 4.9%, respectively) (OR: 2.08, 95% CI: 1.23-3.55, p = 0.007). All communities reported elevated rates of heavy drinking (24.7%, 18.7%, 19.6%, respectively); however, these were higher in the high-affected communities (OR: 1.39, 95% CI: 1.01-1.89, p = 0.04). Severe psychological distress was predicted by fear for one's life in the bushfires, death of someone close to them in the bushfires, and subsequent stressors. One-third of those with severe psychological distress did not receive mental health assistance in the previous month.

CONCLUSIONS

Several years following the Black Saturday bushfires the majority of affected people demonstrated resilience without indications of psychological distress. A significant minority of people in the high-affected communities reported persistent PTSD, depression, and psychological distress, indicating the need for promotion of the use of health and complementary services, community-based initiatives, and family and other informal supports, to target these persistent problems.

Clotrimazole as a pharmaceutical: past, present and future

Clotrimazole is a broad-spectrum antimycotic drug mainly used for the treatment of Candida albicans and other fungal infections. A synthetic, azole antimycotic, clotrimazole is widely used as a topical treatment for tinea pedis (athlete's foot), as well as vulvovaginal and oropharyngeal candidiasis. It displays fungistatic antimycotic activity by targeting the biosynthesis of ergosterol, thereby inhibiting fungal growth. As well as its antimycotic activity, clotrimazole has become a drug of interest against several other diseases such as sickle cell disease, malaria and some cancers. It has also been combined with other molecules, such as the metals, to produce clotrimazole complexes that show improved pharmacological efficacy. Moreover, several new, modified-release pharmaceutical formulations are also undergoing development. Clotrimazole is a very well-tolerated product with few side effects, although there is some drug resistance appearing among immunocompromised patients. Here, we review the pharmaceutical chemistry, application and pharmacology of clotrimazole and discuss future prospects for its further development as a chemotherapeutic agent.

Pentyl-4-yn-valproic acid enhances both spatial and avoidance learning, and attenuates age-related NCAM-mediated neuroplastic decline within the rat medial temporal lobe

2-N-Pentyl-4-pentynoic acid [pentyl-4-yn-valproic acid (VPA)] is an analogue of valproic acid that induces neuritogenesis and increases neural cell adhesion molecule (NCAM) prevalence in cultured neural cells. As memory consolidation involves synapse growth, aided by cell adhesion molecule function, we determined whether or not pentyl-4-yn-VPA had cognition-enhancing properties. Pentyl-4-yn-VPA (16-85 mg/kg) significantly improved water maze learning and task retention when given prior to each training session. Acute administration of pentyl-4-yn-VPA also influenced memory consolidation processes as, when given at 3 h post-passive avoidance training, the amnesia induced by scopolamine given 6 h post-training was prevented in a dose-dependent manner. Chronic administration of pentyl-4-yn-VPA (16.8 or 50.4 mg/kg) also significantly reduced escape latencies in the water maze task, 24 h following the last drug administration. This improved spatial learning was accompanied by enhanced neuroplasticity as the expression of NCAM polysialylated neurons in the infragranular zone of the dentate gyrus and in layer II of the perirhinal and piriform cortex was increased significantly following chronic drug treatment. The cognition-enhancing qualities of pentyl-4-yn-VPA, combined with its ability to attenuate the age-related loss of the NCAM polysialylation state, suggest that it may effectively slow the onset of cognitive decline.

Anti-ischemic and cognition-enhancing properties of NNC-711, a gamma-aminobutyric acid reuptake inhibitor

NNC-711 [1-(2-((diphenylmethylene)amino)oxy)ethyl)-1,2,4,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride], a gamma-aminobutyric acid (GABA) reuptake inhibitor with anticonvulsant activity, was investigated with respect to its cognition-enhancing and neuroprotective potency. In the rat, administration of NNC-711 immediately prior to training prevented amnesia for a passive avoidance task induced by the acetylcholine receptor antagonist scopolamine. NNC-711 was also effective in protecting against ischemia-induced death of CA1 pyramidal neurons in a model of bilateral common carotid artery occlusion in the gerbil. In addition to a neuroprotective activity, NNC-711 exhibited significant cognition-enhancing actions. Daily administration of NNC-711, immediately prior to a spatial learning task, significantly reduced escape latencies in the water maze paradigm in both mature (postnatal day 80) and aged (28 months) rats. All of the above actions exhibited a bell-shaped response with an optimal dose of 0.5-1.0 mg/kg. These investigations with NNC-711 and previous clinical observations on the structurally related anticonvulsant tiagabine confirm the potential of GABA reuptake inhibitors as anti-amnesia and cognition-enhancing agents.

Protein kinase C delta regulates neural cell adhesion molecule polysialylation state in the rat brain

Polysialylation of neural cell adhesion molecule (NCAM PSA) modulates cell-cell homophilic binding and signalling during brain development and the remodelling of discrete brain regions in the adult. Following learning, a transient increase in the frequency of polysialylated neurones occurs in the dentate gyrus of the hippocampal formation, and this has been correlated with the selective retention and/or elimination of synapses that are transiently overproduced during memory consolidation. We now demonstrate that protein kinase C delta (PKCdelta) negatively regulates polysialyltransferase activity in the rat brain during development and also in the hippocampus during memory consolidation, where its down-regulation in the Golgi membrane fraction coincides with the transient increase in NCAM PSA expression. Decreased expression of PKCdelta was also observed in the hippocampus of rats reared in a complex environment and this directly contrasted the significant increase in frequency of hippocampal polysialylated neurones observed in these animals. These effects were isoform-specific as no change in total PKC enzyme activity was detected during memory consolidation and complex environment rearing had no effect on the hippocampal expression of PKCalpha, beta, gamma or epsilon. By sequential immunoprecipitation and immunoblot analysis, phosphorylation of polysialyltransferase protein(s) was (were) demonstrated to occur on both serine and tyrosine residues and this was associated with decreased enzyme activity. Moreover, a similar experimental approach revealed the degree of PKCdelta co-precipitation with polysialyltransferase protein(s) to be inversely correlated with polysialyltransferase activity. These findings support in vitro evidence indicating PKCdelta to regulate polysialyltransferase activity and NCAM polysialylation state.

Consolidation of passive avoidance learning is associated with transient increases of polysialylated neurons in layer II of the rat medial temporal cortex

Within the rat medial temporal lobe, transient modulations of neural cell adhesion molecule (NCAM) polysialylation have been observed to follow spatial learning. These have been attributed to neuroplastic events associated with the processing of information destined for long term memory consolidation. To determine if similar events are associated with avoidance learning, we investigated change in polysialylated cell number in the entorhinal, perirhinal, and piriform cortex, following acquisition of a passive avoidance task in the rat. Direct quantification of polysialylated neurons in layer II of these cortical regions revealed a significant increase in polysialylated cell frequency at 12 h following passive avoidance training. Unlike spatial learning, the increased expression of polysialylated neurons persisted for up to 24-48 h following training. In the more dorsal aspect of the perirhinal/entorhinal cortex, this increase was found to be specific to learning, as it was not observed in animals rendered amnesic with scopolamine. By contrast, change in polysialylated cell frequency in the ventral aspect of the medial temporal lobe was only partially reduced by amnesic doses of scopolamine. The persisting activation of NCAM polysialylation in the more dorsal aspects of the perirhinal and entorhinal cortex is suggested to reflect the need for more extensive synaptic alterations, as compared to those required for the consolidation of spatial learning. Moreover, the neuroplastic modulations observed in the more ventral regions of the entorhinal and perirhinal cortex appear to be a unique aspect of avoidance conditioning that reflects the activation of alternative learning strategies associated with motivational and/or contextual parameters of the task.

Regulation of neural cell adhesion molecule polysialylation state by cell-cell contact and protein kinase C delta

Post-translational modification of neural cell adhesion molecule (NCAM) with alpha2,8-linked polysialic acid, which regulates homophilic adhesion and/or signal transduction events, is crucial to synaptic plasticity in the developing and adult brain. Evidence from in vitro models has implicated polysialylation in the regulation of cell growth, migration, and differentiation. Here, using two in vitro models, we demonstrate that polysialylation is downregulated by cell-cell contact and correlated with a state of neuronal differentiation. Furthermore, we report a role for protein kinase C delta (PKCdelta) in the regulation of NCAM polysialylation. Pharmacological studies using the PKC activator, phorbol myristate acetate, and inhibitors, calphostin-C, and staurosporine, demonstrated PKC activity to be inversely related to NCAM polysialylation in the mouse neuro-2A cell line. Isoform-specific immunoblot studies indicated this effect to be mediated by the calcium-independent PKCdelta isozyme, as its expression was inversely related to NCAM polysialylation state in both neuro-2A and rat PC-12 cell lines. Isoform specificity was further confirmed using the PKCdelta-selective inhibitor rottlerin, which produced a marked increase in PSA expression (36.9+/-5.25 a.u. vs. 24.7+/-0.80 arbitrary units control) coupled with a neuritogenic response. Likewise, decreased expression of PKCdelta was seen in nerve growth factor (NGF)-differentiated PC-12 cells. These findings suggest that the neuronal differentiation process may involve inhibition of PKCdelta, resulting in enhanced morphological plasticity, as evidenced by activation of NCAM polysialylation.

A synthetic peptide ligand of neural cell adhesion molecule (NCAM) IgI domain prevents NCAM internalization and disrupts passive avoidance learning

The neural cell adhesion molecule (NCAM) mediates cell adhesion and signal transduction through trans-homophilic- and/or cis-heterophilic-binding mechanisms. Intraventricular infusions of anti-NCAM have revealed a functional requirement of NCAM for the consolidation of memory in rats and chicks in a specific interval 6-8 h after training. We have now extended these studies to a synthetic peptide ligand of NCAM (C3) with an affinity for the IgI domain and the capability of inhibiting NCAM-mediated neurite outgrowth in vitro. Intraventricular administration of a single 5 microg bolus of C3 strongly inhibited recall of a passive avoidance response in adult rats, when given during training or in the 6-8-h posttraining period. The effect of C3 on memory consolidation was similar to that obtained with anti-NCAM as the amnesia was not observed until the 48-h recall time. The unique amnesic action of C3 during training could be related to disrupted NCAM internalization following training. In the 3-4-h posttraining period NCAM 180, the synapse-associated isoform, was down-regulated in the hippocampal dentate gyrus. This effect was mediated by ubiquitination and was prevented by C3 administration during training. These findings indicate NCAM to be involved in both the acquisition and consolidation of a passive avoidance response in the rat. Moreover, the study provides the first in vivo evidence for NCAM internalization in learning and identifies a synthetic NCAM ligand capable of modulating memory processes in vivo.

Antiproliferative actions of inhalational anesthetics: comparisons to the valproate teratogen

The antiproliferative potential of the volatile anesthetics isoflurane, enflurane and sevoflurane was determined and compared to the valproate teratogen. The in vitro system employed, a G1 phase proliferative arrest endpoint in C6 glioma, has served previously to discriminate agents with known teratogenic potential in vivo. Based on estimated IC(50) values that were within twice the estimated minimum aveolar concentration value, the rank antiproliferative potency of the inhalational anesthetics employed was isoflurane=enflurane>>sevoflurane. Flow cytometric analysis of growth-arrested cell populations failed to reveal specific accumulation in any cell cycle phase and the lack of a G1 phase-specific effect was confirmed by the absence of a transient, time-dependent sialylation event in synchronized cells. The antiproliferative mechanism of volatile anesthetics, and valproate, was mediated at hydrophobic binding sites, as increasing the hydration sphere of the drug-micelle complex, using the hygroscopic qualities of the dimethylsulfoxide vehicle, completely reversed this effect. Our findings suggest inhalational anesthetics lack the specific in vitro characteristics of the valproate teratogen.