Cortisol modifies extinction learning of recently acquired fear in men

Exposure therapy builds on the mechanism of fear extinction leading to decreased fear responses. How the stress hormone cortisol affects brain regions involved in fear extinction in humans is unknown. For this reason, we tested 32 men randomly assigned to receive either 30 mg hydrocortisone or placebo 45 min before fear extinction. In fear acquisition, a picture of a geometrical figure was either partially paired (conditioned stimulus; CS+) or not paired (CS−) with an electrical stimulation (unconditioned stimulus; UCS). In fear extinction, each CS was presented again, but no UCS occurred. Cortisol increased conditioned skin conductance responses in early and late extinction. In early extinction, higher activation towards the CS− than to the CS+ was found in the amygdala, hippocampus and posterior parahippocampal gyrus. This pattern might be associated with the establishment of a new memory trace. In late extinction, the placebo compared with the cortisol group displayed enhanced CS+/CS− differentiation in the amygdala, medial frontal cortex and nucleus accumbens. A change from early deactivation to late activation of the extinction circuit as seen in the placebo group seems to be needed to enhance extinction and to reduce fear. Cortisol appears to interfere with this process thereby impairing extinction of recently acquired conditioned fear.     

Development of twenty-one polymorphic microsatellite markers for the fungus-growing ant,Mycocepurus goeldii (Formicidae: Attini), using Illumina paired-end genomic sequencing

Obligate social parasites, or inquilines, exploit the colonies of free-living social species and evolved at least 80 times in ants alone. Most species of the highly specialized inquiline social parasites are rare, only known from one or very few, geographically isolated populations, and the sexual offspring of most inquiline species mates inside the maternal colony. Therefore, inquiline populations are believed to be small and genetically homogeneous due to inbreeding. To comparatively study the genetic diversity of the socially parasitic fungus-growing ant, Mycocepurus castrator, and its only known host species, Mycocepurus goeldii, and to infer the parasite’s conservation status, we developed 21 microsatellite markers for the host species, M. goeldii, and evaluated whether these markers cross-amplify in the social parasite, M. castrator. We isolated and characterized a total of 21 microsatellite loci for M. goeldii. The loci were screened for 24 individuals from geographically distant and genetically divergent populations in Brazil. The number of alleles per locus ranged from 18 to 4, the observed heterozygosity ranged from 0.25 to 0.636, and the probability of identity values ranged from 0.011 to 0.146. Preliminary analyses show that these markers cross amplify in the closely related social parasite species M. castrator. These newly developed loci provide tools for studying the genetic diversity and the evolution of social parasitism in the Mycocepurus host–parasite system.     

Small bowel obstruction in the virgin abdomen: the need for a mandatory laparotomy explored

Background

A laparotomy is still considered mandatory for patients without previous abdominal surgery presenting with a small bowel obstruction (SBO) because of a perceived high incidence of underlying lesions. However, there is no evidence in literature to support this assumption. We analyzed the etiology of SBO in this subgroup of patients to establish the need for a mandatory laparotomy.

Methods

A retrospective analysis was conducted over a 5-year period. Basic demographics, radiology results, operative findings, and outpatient investigations were analyzed.

Results

Of 689 patients presenting with an SBO, a total of 62 patients, 9.0%, had a virgin abdomen. A known underlying disease (inflammatory bowel disease, malignancy) was the cause in 13 patients. The remaining 49 patients had adhesions in 75.5% and a newly diagnosed malignancy in 10.2% as a cause.

Conclusions

Adhesions are by far the most likely cause of SBO in patients without previous abdominal surgery followed by a small number of newly diagnosed malignancies. Both prevalences are in equal proportion to patients with previous abdominal surgery. A trial of nonoperative management may therefore be justified.     

Dehydroepiandrosterone modulates T-cell response after major abdominal surgery

Background

The immune balance controlled by T-helper (Th)1 and Th2 cells is critical in protecting the host from pathogenic invasion, and its imbalance may increase susceptibility to infection in patients undergoing major surgery. The differentiation of naive T cells to Th1 and Th2 cells is largely driven by cytokines. In addition, steroid hormones have been shown to affect Th1/Th2 balance, particularly in autoimmune diseases. The regulation of Th1/Th2 balance in patients undergoing surgery and its potential clinical relevance remain unclear.

Materials and methods

Blood samples were obtained from patients both before and 2 h after major abdominal surgery. Peripheral blood mononuclear cells were isolated and cultured in wells coated with either anti-CD3 (direct T-cell stimulation) or phytohemagglutinin (PHA) (indirect T-cell stimulation), with or without 10⁻⁵ M dehydroepiandrosterone (DHEA). The release of interleukin (IL)-2, interferon gamma, and IL-10 was measured by an enzyme-linked immunosorbent assay, and the expression of CD4, CD8, and CD69 was determined by flow cytometry.

Results

DHEA decreased the release of IL-2 and IL-10 in directly (anti-CD3) and indirectly (PHA)-stimulated T cells from postoperative samples, whereas the release of interferon gamma in PHA-stimulated T cells was not affected. The distribution of CD4/CD8 was not significantly different after surgery or DHEA. DHEA was associated with a decrease in the expression of the activation marker CD69 on CD4⁺ T cells, whereas the activation of CD8⁺ T cells remained unchanged.

Conclusions

These results demonstrate that DHEA plays a critical role in controlling Th1/Th2 balance in the immediate postoperative period. Attenuation of both the Th1 and Th2 responses has been suggested to have immunoprotective effects. The role of DHEA in the regulation of Th1/Th2 balance in patients undergoing major abdominal surgery may, therefore, also be of significant clinical relevance and warrants further investigation.     

Bone Flap Necrosis After Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction

Background

Autologous bone flap reinsertion follows as a second surgical intervention after decompressive craniectomy in patients with malignant middle cerebral artery (MCA) infarction. In addition to surgery-related short-term complications, aseptic resorption of the reimplanted bone flap is a possible long-term problem which has not yet been sufficiently elucidated in these patients.

Methods

A total of 109 patients who had undergone decompressive hemicraniectomy for malignant MCA infarction in our institution between September 1994 and December 2011 were included in the study. Clinical and radiological findings were retrieved retrospectively. Aseptic bone necrosis was classified into two categories based on computer tomographic features.

Results

A total of 76 patients received their own cryoconserved bone flap (mean age 54.34 ± 10.73 years; 49 males). The overall short-term complication rate was 9.2 %. Bone flap necrosis occurred in 26 patients (22.8 %) with 7 flaps showing signs of surgically relevant type II necrosis after a median time of 14 months (interquartile range [IQR] 4–22).

Conclusions

There is a noticeable complication rate in patients undergoing bone flap reinsertion after hemicraniectomy due to malignant MCA infarction. Aseptic bone necrosis represents a significant complication during long-term follow-up. The pathophysiological mechanisms remain unclear and more efforts should be undertaken to understand and possibly prevent this complication in these patients.     

Minimally Invasive Endoscopic Surgery for Treatment of Spontaneous Intracerebral Hematomas: A Single-Center Analysis

Background

Endoscopic minimally invasive surgery to evacuate ICH has been reported to be more effective than conservative treatment or standard surgical craniotomy. However, most of these reports are based on Asian populations, while European reports do not exist. Here, we, therefore, report our experience from a European neurosurgical stroke center.

Methods

The variables assessed were patient characteristics, technical aspects of surgery, surgical complications, the outcomes grade of hematoma evacuation, 30-day mortality, and functional outcome (defined by modified Rankin Scale, mRS). The mRS was dichotomized into favorable (0–3) and unfavorable outcome (4–6). Mortality was compared to external evidence on conservatively and surgically treated patients by Poisson regression analysis with adjustment for ICH score.

Results

Thirty-four patients with ICH were analyzed. The mean age was 62 (standard deviation [SD] 12) years, mean hematoma volume (SD) was 84 (35) ml, and mean time from onset to surgery (SD) was 17 (10) h. Operative times did not exceed 1.5 h. A significant mean hematoma reduction (SD) from 84 (35) ml to 21 (30) ml (p < 0.0001) could be achieved, resulting in a median evacuation rate of 87 %. Early complications related to surgery did not occur. A favorable outcome was observed in 44 % of the patients. Overall, 30-day mortality was 18 %. The relative risk of mortality compared to conventional treatment from other studies was 32 % (95 % confidence interval 23–43 %, p = 0.02).

Conclusions

This European surgical stroke center series of an endoscopic operative technique demonstrates safety and efficacy with regard to reduction of hematoma size in patients with large and space-occupying spontaneous ICH. The study suggests that low mortality and acceptable outcomes may be achievable by minimally invasive hematoma surgery. Whether this technique reduces long-term morbidity compared to standard treatment needs to be further investigated in larger prospective randomized controlled trials.