Cerebral metabolism after early decompression craniotomy following controlled cortical impact injury in rats

After traumatic brain injury, a cascade of metabolic changes promotes the development of secondary brain damage. In this study, we examined metabolic changes in rats in the acute stage after trauma. Furthermore, we investigated the effect of a very early decompression craniotomy on intracranial pressure (ICP) and on metabolic parameters. For this study, a moderate controlled cortical impact injury (CCII) on rats was performed. The observation time was 180 minutes after trauma. ICP was measured continuously and microdialysate samples were collected every 30 minutes from the peri-contusional region. As representative metabolic parameters, glutamate, lactate, lactate/pyruvate ratio (L/P ratio), and glucose concentrations were measured. Compared to sham-operated animals, a significant, sustained decrease in glucose concentration and increase in L/P ratio occurred immediately after CCII. Additionally, delayed increase in lactate and glutamate concentrations occurred 60 minutes after trauma. After this initial peak, glutamate concentrations declined continuously via the observation time and reached levels comparable to sham-operated animals. In our model, thus we could detect a very early deterioration of glucose utilization and energy supply after trauma that recovered, due to the moderate intensity of the trauma, within 60 minutes without leading to ischemia in the peri-contusional region. Following decompression craniotomy, the increase of intracranial pressure could be reduced significantly. Any significant beneficial effects on metabolic changes, however, could not be proven in this very early stage after moderate CCII.     

Prenatal stress changes learning strategies in adulthood

It is well known that stressful experiences may shape hippocampus‐dependent learning and memory processes. However, although most studies focused on the impact of stress at the time of learning or memory testing, very little is known about how stress during critical periods of brain development affects learning and memory later in life. In this study, we asked whether prenatal stress exposure may influence the engagement of hippocampus‐dependent spatial learning strategies and caudate nucleus‐dependent response learning strategies in later life. To this end, we tested healthy participants whose mothers had experienced major negative life events during their pregnancy in a virtual navigation task that can be solved by spatial and response strategies. We found that young adults with prenatal stress used rigid response learning strategies more often than flexible spatial learning strategies compared with participants whose mothers did not experience major negative life events during pregnancy. Individual differences in acute or chronic stress do not account for these findings. Our data suggest that the engagement of hippocampal and nonhippocampal learning strategies may be influenced by stress very early in life. © 2012 Wiley Periodicals, Inc.     

Regional networks underlying interhemispheric connectivity: an EEG and DTI study in healthy ageing and amnestic mild cognitive impairment

Interhemispheric coherence derived from electroencephalogram (EEG) recordings is a measure of functional interhemispheric connectivity. Diffusion tensor imaging (DTI) determines the integrity of subcortical fiber tracts. We studied the pattern of subcortical fiber tracts underlying interhemispheric coherence and its alteration in 16 subjects with amnestic mild cognitive impairment (MCI), an at risk syndrome for Alzheimer's disease, and 20 cognitively healthy elderly control subjects using resting state EEG and high resolution DTI at 3 T. We used a multivariate network approach based on principal component analysis to determine effects of coherence on the regional pattern of diffusivity. Temporo-parietal coherence in the alpha band was significantly correlated with diffusivity in predominantly posterior white matter tracts including posterior corpus callosum, parietal, temporal and occipital lobe white matter, thalamus, midbrain, pons, and cerebellum, both in MCI subjects and controls (P < 0.05). In MCI subjects, frontal coherence in the alpha band was significantly correlated with a predominately frontal pattern of diffusivity including fiber tracts of the anterior corpus callosum, frontal lobe white matter, thalamus, pons, and cerebellum (P < 0.05). The study provides a methodology to access specific networks of subcortical fiber tracts subserving the maintenance of interhemispheric resting state coherence in the human brain.     

Evaluation of cognition, structural, and functional MRI in juvenile myoclonic epilepsy

Purpose:  Previous studies using advanced imaging techniques have suggested subtle structural and functional changes in patients with juvenile myoclonic epilepsy (JME), mainly associated with the frontal lobes. In addition, it has been reported that these patients show neuropsychological deficits, often summarized as frontal lobe dysfunction. The aim of this study was a comprehensive analysis of neuropsychological parameters, and functional and structural magnetic resonance imaging (MRI) in an independent cohort of patients with JME.
Methods:  We studied 19 JME patients and 20 age-, sex-, and education-matched controls using a battery of standardized neuropsychological tests, optimized voxel-based morphometry (VBM), and two domain-specific working-memory paradigms combined with functional MRI (fMRI).
Results:  Our investigations did not reveal statistically significant differences between the groups of JME patients and normal controls in either the VBM or the fMRI study of working memory. The neuropsychological examination showed a slightly worse performance for the JME patients across most tests used, reaching statistical significance for semantic and verbal fluency.
Conclusions:  In our cohort of JME patients, we could not reproduce the findings of frontal gray matter changes from previous studies, and we could not detect an fMRI correlate of previously reported differences in working memory in JME. The neuropsychological deficits may be attributed partially to antiepileptic medication. We conclude that structural and functional frontal lobe deficits in JME patients have to be interpreted with care. One reason for a variation between different cohorts may be the genetic heterogeneity of the disease.     

Correlation of body mass index and menopausal status with the intra-tumoral estrogen system in invasive breast cancer

Objective. Obesity increases breast cancer risk in post-menopausal women. This is, in part, due to elevated non-glandular aromatase activity, resulting in higher estradiol serum levels. We tested the hypothesis that obesity and menopausal status influence the intra-tumoral estrogen system of breast cancer tissue.

Design. Breast cancer tissue and fasting serum were collected from 26 female patients. After microdissection of the frozen samples, RNA was isolated, and expression of estrogen receptor (ER)α, ERβ1, ERβ2, ERβ5, CYP19 aromatase and steroid sulfatase was measured on mRNA level by means of real time RT-PCR. Fasting estradiol serum levels were analysed by ELISA.

Results. Post-menopausal women older than 70 years exhibited a significantly higher expression both of steroid sulfatase and ERα than did pre-menopausal women younger than 50 years. We identified a significant positive correlation between body mass index (BMI) and lymphovascular/vascular invasion. A significant inverse correlation between ERα and ERβ2 expression was identified in invasive breast cancer tissue irrespective of BMI or menopausal status.

Conclusion. In conclusion, we report an association between menopausal status – but not BMI – and the intra-tumoral expression of steroid sulfatase and ERα. Our observation that BMI was associated with invasiveness supports the hypothesis that metabolic factors are able to affect essential features of breast cancer.     

Preoperative HE4 expression in plasma predicts surgical outcome in primary ovarian cancer patients: Results from the OVCAD study

ObjectivesEpithelial ovarian cancer (EOC) is the major cause of death due to gynecological malignancies. The most important prognostic factors are residual tumor mass after surgery and platinum-response. No predictive biomarkers are available to identify patients who will benefit from standard treatment. The aim of our study was to analyze the role of HE4 in predicting surgical and clinical outcome in primary EOC.MethodsIn the European multicentric project “OVCAD”, 275 consecutive patients with primary EOC were enrolled. Patients were eligible if radical cytoreductive surgery was performed and platinum-based chemotherapy was applied. Plasma and ascites samples were collected before or during surgery. The concentrations of HE4 and CA125 was determined using ELISA and Luminex technique, respectively.ResultsMedian age at first diagnosis was 58 years (range 18–85 years). Most patients presented with advanced stage disease, FIGO III or IV (94.6%), grades II–III (96%) and serous histology (86.2%). In most cases a complete cytoreduction to no residual tumor mass was achieved (68.4%). Higher plasma HE4 levels correlated with poor surgery outcome in terms of macroscopically residual tumor mass (p < 0.001) and platinum-resistance (p = 0.009). Plasma CA125 and the risk index (HE4 and CA125) were independent predictive factors for surgical outcome (p = 0.001, OR = 3.37, 95% CI = 1.61–7.06 and p < 0.001, OR = 6,041, 95% CI = 2.33–15.65, respectively). FIGO stage III was an independent predictive factor for platinum response (p = 0.039, OR = 0.436, 95% CI = 0.198–0.960).ConclusionsThe presented data are showing that the combination of HE4 and CA125 expression in plasma might predict the surgical outcome in EOC and by this may have a prognostic impact on PFS and OS.     

The importance of cationic amino acid transporter expression in human skin

Inducible nitric oxide synthase and arginase activities are acknowledged as important players in human skin epidermal function. For proper enzyme function the substrate availability of L-arginine for both enzymes and thus its transport across the cell membrane via the y+-system (also named cationic amino acid transporters) is critical. Here, we examine the expression of cationic amino acid transporters and their functional role in modulating inducible nitric oxide synthase and arginase activities in human skin and primary keratinocytes, fibroblasts and endothelial cells as well as their impact on keratinocyte proliferation. Skin biopsies were found to express constitutively both cationic amino acid transporter-1 and cationic amino acid transporter-2 mRNA, an expression pattern known to occur in hepatocytes and muscle cells only. To determine the cellular components expressing cationic amino acid transporter, we analyzed the expression patterns in the different human skin cell types in vitro, i.e., in fibroblasts, dermal endothelial cells, and keratinocytes as well as in the HaCaT cell line. An ubiquitous cationic amino acid transporter-1 mRNA expression was found in all cells, whereas constitutive cationic amino acid transporter-2 mRNA expression occurs in resident keratinocytes and dermal endothelial cells only. De novo induction of cationic amino acid transporter-2 and inducible nitric oxide synthase by proinflammatory cytokines was seen in fibroblasts and HaCaT. Competitive inhibition of the cationic amino acid transporter-mediated L-arginine transport by culturing primary human keratinocytes in the presence of increased L-lysine concentration led to decreased inducible nitric oxide synthase and arginase activities with a concomitant significant decrease in keratinocyte proliferation. In summary, our results demonstrate that human keratinocytes constitutively express cationic amino acid transporters 1 and 2 and that cationic amino acid transporter mediated L-arginine influx, is essential for both inducible nitric oxide synthase and arginase enzyme activities, which in turn modulate proliferation and differentiation of human epidermal skin cells.     

Maturation of the pituitary-adrenal function in rat fetuses

Plasma adrenocorticotropic hormone (ACTH) and corticosterone were detectable in fetal plasma on day 16 of pregnancy. Thereafter, the levels of both hormones increased steadily in a parallel manner and reached a peak on day 19 of pregnancy. Administration of an antiserum anti-rat corticotropin-releasing factor (CRF) to pregnant rats was followed by a significant decrease in fetal plasma corticosterone as early as day 17. Plasma ACTH measured under the same experimental conditions on day 19 of gestation was also significantly decreased. Similar results have been obtained with fetal plasma collected from adrenalectomized pregnant rats, indicating that the plasma corticosterone decrease in fetuses after immunoneutralization of CRF reflects changes in fetal adrenal secretion and not a diminution of corticosterone transfer from the maternal to the fetal circulation. These results show that endogenous CRF begins to play a physiological role in the regulation of ACTH and corticosterone secretion as early as in 17-day-old fetuses. This effect may occur before the connections between the neurosecretory CRF axons and the hypophysial portal capillaries have been established. Therefore, endogenous CRF may enter the hypophysial portal circulation after intercellular diffusion in hypothalamic tissue.