Low estradiol is linked to increased skin conductance, but not subjective anxiety or affect, in response to an impromptu speech task.

Low estradiol is associated with impaired extinction of conditioned physiological fear responses (e.g. skin conductance) in females. As fear extinction is the laboratory basis of exposure therapy for anxiety disorders, it has been speculated that estradiol may be related to the effectiveness of treatment for anxiety. The present study extended past research by examining whether estradiol is related to physiological and subjective fear responses during the impromptu speech task, where participants perform a surprise speech to camera. This task elicits psychosocial fear, and thus has relevance for social anxiety disorder (SAD). We used a quasi-experimental design with two groups of women: 39 naturally cycling women, and 19 women taking hormonal contraceptives. Based on the measured serum levels, naturally cycling women were further divided into women with higher- vs. lower estradiol levels. Compared to those with higher estradiol, women with lower estradiol, and those using hormonal contraceptives (chronically suppressed estradiol) displayed higher speech-elicited skin conductance yet reported no differences in subjective anxiety or affect. Conversely, irrespective of estradiol status, compared to those with low self-reported social anxiety, participants with higher social anxiety exhibited greater subjective anxiety and affect, yet no differences in skin conductance. These results demonstrate that the relationship between estradiol and physiological fear responses extends to psychosocial tasks. However, the dissociations between physiological and subjective measures highlight the need to consider the relevance of different response outputs so that the potential impact of estradiol on the treatment of anxiety disorders can be better understood.

Manipulation of host and parasite microbiotas: Survival strategies during chronic nematode infection.

Intestinal dwelling parasites have evolved closely with the complex intestinal microbiota of their host, but the significance of the host microbiota for metazoan pathogens and the role of their own intestinal microbiota are still not fully known. We have found that the parasitic nematode Trichuris muris acquired a distinct intestinal microbiota from its host, which was required for nematode fitness. Infection of germ-free mice and mice monocolonized with Bacteroides thetaiotaomicron demonstrated that successful T. muris infections require a host microbiota. Following infection, T. muris-induced alterations in the host intestinal microbiota inhibited subsequent rounds of infection, controlling parasite numbers within the host intestine. This dual strategy could promote the long-term survival of the parasite within the intestinal niche necessary for successful chronic nematode infection.

Effects of a multimodal intervention on gait and balance of subjects with progressive multiple sclerosis: a prospective longitudinal pilot study.

PURPOSE: To investigate the effects of a multimodal intervention including a modified Paleolithic diet, nutritional supplements, stretching, strengthening exercises with electrical stimulation of trunk and lower limb muscles, meditation and massage on walking performance and balance of subjects with progressive multiple sclerosis (MS). MATERIALS AND METHODS: Twenty subjects with mean (standard deviation) age of 51.7 (6.4) years and Expanded Disability Status Scale score of 6.2 (1) participated in a 12-month study. Assessments were completed at baseline, 3, 6, 9, and 12 months. RESULTS: The entire cohort did not show significant changes in any of the assessments over 12 months except higher speed of walking toward the 10 feet mark during timed up and go (TUG) test at 6 months compared with baseline (mean change 7.9 cm/s [95% confidence interval {CI}]: 0.3, 15.2; p=0.041). Sub-group analysis revealed that 50% subjects (n=10) showed decrease in TUG time from baseline to at least 3 of 4 time-points post-intervention and were considered as responders (TUG-Res), the remaining 10 subjects were considered as nonresponders (TUG-NRes). Over 12 months, TUG-Res showed decreased mean TUG time by 31% (95% CI: -52%, -2%), increased median Berg Balance Scale scores (42 to 47), 30% increase in mean timed 25-foot walk speed (>20% considered clinically significant) and increased speed of walk toward 10 feet mark during TUG by 11.6 cm/s (95% CI: -3.0, 25.9) associated with increases in step lengths and decrease in step duration. TUG-NRes showed deterioration in walking ability over 12 months. Comparison of TUG-Res and TUG-NRes showed no significant differences in adherence to intervention but better stride duration and longer step length at baseline for TUG-Res than for TUG-NRes (p<0.05). CONCLUSION: A multimodal lifestyle intervention may improve walking performance and balance in subjects with progressive MS who have mild-to-moderate gait impairment, whereas subjects with severe gait impairments may not respond to this intervention. Future trials should assess effects of this intervention in subjects with MS during early stages of the disease.

Estradiol levels in women predict skin conductance response but not valence and expectancy ratings in conditioned fear extinction.

Anxiety disorders are more prevalent in women than men. One contributing factor may be the sex hormone estradiol, which is known to impact the long term recall of conditioned fear extinction, a laboratory procedure that forms the basis of exposure therapy for anxiety disorders. To date, the literature examining estradiol and fear extinction in humans has focused primarily on physiological measures of fear, such as skin conductance response (SCR) and fear potentiated startle. This is surprising, given that models of anxiety identify at least three important components: physiological symptoms, cognitive beliefs, and avoidance behavior. To help address this gap, we exposed women with naturally high (n=20) or low estradiol (n=19), women using hormonal contraceptives (n=16), and a male control group (n=18) to a fear extinction task, and measured SCR, US expectancy and CS valence ratings. During extinction recall, low estradiol was associated with greater recovery of SCR, but was not related to US expectancy or CS evaluation. Importantly, women using hormonal contraceptives showed a dissociation between SCR and cognitive beliefs: they exhibited a greater recovery of SCR during extinction recall, yet reported similar US expectancy and CS valence ratings to the other female groups. This divergence underscores the importance of assessing multiple measures of fear when examining the role of estradiol in human fear extinction, especially when considering the potential of estradiol as an enhancement for psychological treatments for anxiety disorders.