Role of emotional processing in depressive responses to sex-hormone manipulation: a pharmacological fMRI study.

Sex-hormone fluctuations may increase risk for developing depressive symptoms and alter emotional processing as supported by observations in menopausal and pre- to postpartum transition. In this double-blinded, placebo-controlled study, we used blood-oxygen level dependent functional magnetic resonance imaging (fMRI) to investigate if sex-steroid hormone manipulation with a gonadotropin-releasing hormone agonist (GnRHa) influences emotional processing. Fifty-six healthy women were investigated twice: at baseline (follicular phase of menstrual cycle) and 16 ± 3 days post intervention. At both sessions, fMRI-scans during exposure to faces expressing fear, anger, happiness or no emotion, depressive symptom scores and estradiol levels were acquired. The fMRI analyses focused on regions of interest for emotional processing. As expected, GnRHa initially increased and subsequently reduced estradiol to menopausal levels, which was accompanied by an increase in subclinical depressive symptoms relative to placebo. Women who displayed larger GnRHa-induced increase in depressive symptoms had a larger increase in both negative and positive emotion-elicited activity in the anterior insula. When considering the post-GnRHa scan only, depressive responses were associated with emotion-elicited activity in the anterior insula and amygdala. The effect on regional activity in anterior insula was not associated with the estradiol net decline, only by the GnRHa-induced changes in mood. Our data implicate enhanced insula recruitment during emotional processing in the emergence of depressive symptoms following sex-hormone fluctuations. This may correspond to the emotional hypersensitivity frequently experienced by women postpartum.

Resting-state connectivity of pre-motor cortex reflects disability in multiple sclerosis.

OBJECTIVE: To characterize the relationship between motor resting-state connectivity of the dorsal pre-motor cortex (PMd) and clinical disability in patients with multiple sclerosis (MS). MATERIALS AND METHODS: A total of 27 patients with relapsing-remitting MS (RR-MS) and 15 patients with secondary progressive MS (SP-MS) underwent functional resting-state magnetic resonance imaging. Clinical disability was assessed using the Expanded Disability Status Scale (EDSS). Independent component analysis was used to characterize motor resting-state connectivity. Multiple regression analysis was performed in SPM8 between the individual expression of motor resting-state connectivity in PMd and EDSS scores including age as covariate. Separate post hoc analyses were performed for patients with RR-MS and SP-MS. RESULTS: The EDSS scores ranged from 0 to 7 with a median score of 4.3. Motor resting-state connectivity of left PMd showed a positive linear relation with clinical disability in patients with MS. This effect was stronger when considering the group of patients with RR-MS alone, whereas patients with SP-MS showed no increase in coupling strength between left PMd and the motor resting-state network with increasing clinical disability. No significant relation between motor resting-state connectivity of the right PMd and clinical disability was detected in MS. CONCLUSIONS: The increase in functional coupling between left PMd and the motor resting-state network with increasing clinical disability can be interpreted as adaptive reorganization of the motor system to maintain motor function, which appears to be limited to the relapsing-remitting stage of the disease.

Observation of non-Markovian dynamics of a single quantum dot in a micropillar cavity.

We measure the detuning-dependent dynamics of a quasiresonantly excited single quantum dot coupled to a micropillar cavity. The system is modeled with the dissipative Jaynes-Cummings model where all experimental parameters are determined by explicit measurements. We observe non-Markovian dynamics when the quantum dot is tuned into resonance with the cavity leading to a nonexponential decay in time. Excellent agreement between experiment and theory is observed with no free parameters providing the first quantitative description of an all-solid-state cavity QED system based on quantum dot emitters.

Evidence for a Na+/Ca2+ exchange mechanism in frog skin epithelium.

In the present study we investigated the possible existence of a Na+/Ca2+ exchange mechanism in the basolateral membrane of the frog skin epithelium and whether such a mechanism plays a role in the regulation of transepithelial Na+ transport. Cytosolic calcium ([Ca2+]i) was measured with the probe fura-2 in a set-up in which pieces of tissue were mounted on the stage of an epifluorescence microscope. Na+ transport was measured as the amiloride-sensitive short-circuit current (Isc) using a conventional voltage clamp. Basal [Ca2+]i was 65+/-6 nM (n=15). Removal of Na+ from the mucosal solution had no effect on [Ca2+]i. When Na+ was removed from the serosal solution, [Ca2+]i increased biphasically to a peak of 220+/-38 nM (n=8, P=0.006). Readdition of Na+ to the serosal solution returned [Ca2+]i to control level. The serosal Na+ gradient and changes in [Ca2+]i were closely correlated; stepwise changes in serosal Na+ were followed by stepwise changes in [Ca2+]i. These observations indicate the existence of a Na+/Ca2+ exchange mechanism in the basolateral membrane of the frog skin epithelium. The transepithelial Na+ transport decreased from 13.2+/-1.8 to 9.2+/-1.5 microA cm-2 (n=8, P=0.049) when Na+ was omitted from the serosal solution. When this protocol was repeated in the absence of serosal Ca2+, Na+ transport decreased similarly from 16.7+/-1.7 to 11.6 +/-1. 8 microA cm-2 (n=6, P=0.004). We conclude that it is unlikely that the observed decrease in Isc after removal of serosal Na+ is due to an increase in [Ca2+]i per se.

[Emergency echocardiography in Denmark]. / Ekkokardiografi uden for dagtid i Danmark.

In spring 1997, all medical departments in Denmark and the Faroe Islands, not including cardiological centers, were asked to reply to a questionnaire concerning their ability to perform echocardiography at hours different from normal daytime. The response rate was 94.5%. In 21 (30.4%) of 69 departments none of the senior doctors on duty were able to perform echocardiography. In only eight (11.6%) of the departments were more than 50% of the senior doctors on duty able to perform echocardiography (M-mode/2D). Echocardiography is the most informative investigation for patients with suspected acute heart failure or with acute dyspnoea of unknown cause. In these cases acutely performed echocardiography will often be of critical diagnostic value and thereby deciding for correct and rapid therapy. This investigation shows that only a very small fraction of the medical departments in Denmark are able to perform acute echocardiography on a 24-hour basis.

[Peripheral polyneuropathy in legionellosis]. / Perifer polyneuropati ved legionellose.

Neurologic manifestations of Legionnaires' disease occur quite often, although neuropathies are not as common as abnormal mentation. A case story of a 41 year-old woman with severe Legionnaires' disease is presented. After two months on the intensive care unit she appeared to suffer from polyneuropathy in both legs EMG revealed severe polyneuropathy. The symptoms were still present after nine months. The pathogenesis is discussed.