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Search Results: 1 - 10 of 1880 matches for " Nadia Lakis "
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Individuals Diagnosed with Schizophrenia Assign Emotional Importance to Neutral Stimuli: An fMRI Study
Nadia Lakis,Adrianna Mendrek
ISRN Psychiatry , 2013, DOI: 10.1155/2013/965428
Abstract: The majority of functional neuroimaging studies investigating neural correlates of emotion processing in schizophrenia report a significant deficit in limbic structures activation in patients relative to control participants. Recently it has been suggested that this apparent “deficit” could be due to an enhanced sensitivity of the neutral material in individuals diagnosed with schizophrenia, rather than due to their inefficiency in emotion processing. The purpose of the present study was to test this supposition and verify if the potential effect is present in both men and women diagnosed with schizophrenia. In order to do that we examined the pattern of cerebral activation associated with processing of neutral stimuli in schizophrenia. Thirty-seven schizophrenia patients and 37 healthy controls viewed neutral and emotional images while in a functional magnetic resonance imaging scanner. Schizophrenia patients rated the neutral images as more emotionally salient than controls. Additionally, patients showed significant activation during processing of neutral images in limbic and prefrontal regions; similar areas were underactivated in patients relative to controls during processing of emotional information. Investigation of sex differences revealed that the enhanced responsiveness to the emotionally neutral material was attributed primarily to men with schizophrenia. 1. Introduction Functional neuroimaging studies, which explored processing of emotional material in schizophrenia, have often reported “deficits” in cerebral activation in patients compared to control participants in various limbic, paralimbic, and prefrontal regions (e.g., [1–4]). A few other studies documented “abnormal overactivation” in patients relative to controls or no difference between the groups [5–10]. These divergent findings have been attributed to the type of emotional task (passive viewing, emotion identification, emotional memory, etc.) and to the characteristics of the recruited patients (first-episode versus chronic, medicated versus unmediated, presence of prominent negative versus prominent positive symptoms, etc.). However, what could have played an equally or even more important role in the obtained results is the kind of functional neuroimaging contrast used in the statistical analysis. It should be pointed out to readers less familiar with the functional neuroimaging literature that the functional magnetic resonance imaging (fMRI) studies in various clinical populations (including schizophrenia and related psychoses) have relied primarily on comparisons between two
Emotion Processing in Women with Schizophrenia Is Menstrual Cycle Phase and Affective Valence Dependent: An fMRI Study
Adrianna Mendrek,Josiane Bourque,Annie Dubé,Nadia Lakis
ISRN Psychiatry , 2012, DOI: 10.5402/2012/656274
Abstract:
Emotion Processing in Women with Schizophrenia Is Menstrual Cycle Phase and Affective Valence Dependent: An fMRI Study
Adrianna Mendrek,Josiane Bourque,Annie Dubé,Nadia Lakis,Julie Champagne
ISRN Psychiatry , 2012, DOI: 10.5402/2012/656274
Abstract: Despite a large number of functional neuroimaging investigations of emotion processing in schizophrenia, very few have included women. In the present study 21 schizophrenia and 23 healthy women underwent functional MRI (3T) on two occasions (during the follicular and luteal phase of their menstrual cycle) while viewing blocks of emotionally negative, positive and neutral images. During exposure to negatively charged images patients showed relatively less activations than controls during the luteal phase, but no between-group differences were observed during the follicular phase. In contrast, the exposure to positively valenced material produced no significant interaction, but the main effect of group; schizophrenia patients exhibited less activation than healthy controls during both phases of the menstrual cycle. This is the first study demonstrating that atypical neural activations associated with emotion processing in women diagnosed with schizophrenia depend on the menstrual cycle phase and on the affective valence of presented stimuli. 1. Introduction Schizophrenia is a complex and clinically heterogeneous psychiatric disorder with unknown etiology, age at onset in late adolescence/early adulthood, and a lifetime prevalence of approximately 1% [1, 2]. One of the hallmark characteristics of this devastating disorder is a disturbance in emotion processing, which has been demonstrated in numerous behavioral, physiological, and functional neuroimaging investigations that employed tasks ranging from passive viewing of emotional material, through to facial emotion identification and emotional memory [3–8]. Although widely investigated, the neural correlates of atypical emotion processing in schizophrenia patients are still not well understood. For instance, while the majority of studies report diminished activations in patients relative to healthy subjects in several regions implicated in affect (e.g., hippocampus, amygdala, medial prefrontal, orbitofrontal cortex, and cingulate cortices) (e.g., [9–12]), others have found no effect or increased neural reactivity to emotionally charged material (e.g., [13–15]). In our recent study we have observed diminished activations during retrieval of negatively valenced emotional material but enhanced activations during positively valenced condition in clinically stable schizophrenia patients relative to controls [8]. Thus, one important factor to consider is affective valence of presented stimuli. Another important variable is gender of tested individuals, as numerous studies in the general population have
Progesterone and Cerebral Function during Emotion Processing in Men and Women with Schizophrenia
Julie Champagne,Nadia Lakis,Josiane Bourque,Emmanuel Stip,Olivier Lipp,Adrianna Mendrek
Schizophrenia Research and Treatment , 2012, DOI: 10.1155/2012/917901
Abstract: Schizophrenia has been associated with disturbed levels of sex-steroid hormones, including estrogen and testosterone. In the present study we have examined the implication of a less studied hormone progesterone. Forty-three patients with schizophrenia (21 women) and 43 control participants (21 women) underwent functional MRI while viewing emotionally positive, negative, and neutral images. Blood samples were taken prior to the scanning session to evaluate progesterone levels. Simple regression analyses between levels of progesterone and brain activations associated with emotion processing were performed using SPM5. A positive correlation was found between progesterone levels and brain activations during processing of emotionally charged images in both healthy and schizophrenia men, but no significant relationship was revealed in women. These preliminary results indicate that progesterone is significantly associated with brain activations during processing of positive and negative affect in healthy and schizophrenia men, but not in women. Further investigation is warranted.
Progesterone and Cerebral Function during Emotion Processing in Men and Women with Schizophrenia
Julie Champagne,Nadia Lakis,Josiane Bourque,Emmanuel Stip,Olivier Lipp,Adrianna Mendrek
Schizophrenia Research and Treatment , 2012, DOI: 10.1155/2012/917901
Abstract: Schizophrenia has been associated with disturbed levels of sex-steroid hormones, including estrogen and testosterone. In the present study we have examined the implication of a less studied hormone progesterone. Forty-three patients with schizophrenia (21 women) and 43 control participants (21 women) underwent functional MRI while viewing emotionally positive, negative, and neutral images. Blood samples were taken prior to the scanning session to evaluate progesterone levels. Simple regression analyses between levels of progesterone and brain activations associated with emotion processing were performed using SPM5. A positive correlation was found between progesterone levels and brain activations during processing of emotionally charged images in both healthy and schizophrenia men, but no significant relationship was revealed in women. These preliminary results indicate that progesterone is significantly associated with brain activations during processing of positive and negative affect in healthy and schizophrenia men, but not in women. Further investigation is warranted. 1. Introduction There is some evidence of a relationship between sex-steroid hormones (i.e., estrogen, testosterone, and less commonly progesterone) and emotion processing in the general population [1–3]. Fluctuations in estrogen and progesterone have been linked with increased vulnerability to mood disorders in women, while elevated levels of testosterone have been primarily associated with antisocial behaviours, behaviours of dominance, and aggressiveness in both men and women [4]. In schizophrenia, some studies have found abnormal levels of estrogens and testosterone in patients, but the results have been equivocal and sometimes attributed to the antipsychotic-induced hyperprolactinemia, which may alter levels of gonadal hormones [5]. Despite numerous studies and clinical observations of lower relapse of clinical symptoms during pregnancy, high relapse postpartum, and the fluctuation of symptoms across the menstrual cycle (attributed typically to the changing levels of estrogens), a link between progesterone and affect in schizophrenia has yet to be examined [6]. The little emphasis that has been placed on the relationship between progesterone and emotional functioning has been explored primarily in healthy women because this hormone is a female reproductive hormone. Nonetheless, it is produced in both men and women, and recent evidence suggests that it is implicated in brain function of both sexes. Thus, progesterone has been shown to play an important role in mood regulation [7],
Supersonic Flutter of a Spherical Shell Partially Filled with Fluid  [PDF]
Mohamed Menaa, Aouni A. Lakis
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.43014
Abstract:

In the present study, a hybrid ?nite element method is applied to investigate the dynamic behavior of a spherical shell partially filled with fluid and subjected to external supersonic airflow. The structural formulation is a combination of linear spherical shell theory and the classic finite element method. In this hybrid method, the nodal displacements are derived from exact solution of spherical shell theory rather than approximated by polynomial functions. Therefore, the number of elements is a function of the complexity of the structure and it is not necessary to take a large number of elements to get rapid convergence. Linearized first-order potential (piston) theory with the curvature correction term is coupled with the structural model to account for aerodynamic loading. It is assumed that the fluid is incompressible and has no free surface effect. Fluid is considered as a velocity potential at each node of the shell element where its motion is expressed in terms of nodal elastic displacements at the ?uid-structure interface. Numerical simulation is done and vibration frequencies are obtained. The results are validated using numerical and theoretical data available in literature. The investigation is carried out for spherical shells with different boundary conditions, geometries, filling ratios, flow parameters, and radius to thickness ratios. Results show that the spherical shell loses its stability through coupled-mode flutter. This proposed hybrid finite element method can be used efficiently for analyzing the flutter of spherical shells employed in aerospace structures at less computational cost than other commercial FEM software.

Advocacy and Policy Change in the Multilevel System of the European Union: A Case Study within Health Policy  [PDF]
Nadia Carboni
Open Journal of Political Science (OJPS) , 2012, DOI: 10.4236/ojps.2012.23005
Abstract: Health policy is basically Member States’ competence. However, the European Union has recently raised a number of key questions facing both (pharmaceutical) industries and public health interests. By applying the Advocacy Coalition Framework, the paper sheds light on policy change within the European multilevel system. The analysis is based on a case-study strategy. Two processes in the pharmaceutical policy are taken into account: the “Pharma Forum” and the “Pharma Package”. They both concern “information to patient”—a controversial policy issue at the crossroad of competing pressures.
Environmental Parameters Affecting the Species Diversity Along the Aliakmon River, North Greece
Ilias F. Ilias,Christos Lakis,Agapi Z. Papazafeiriou
Pakistan Journal of Biological Sciences , 2008,
Abstract: The annual distribution of aquatic and coastal macrophytes in five selected sites along the Aliakmon River was studied from January 2005 to December 2005 in Northern Greece. Soil and water chemical parameters in these sites were also evaluated. A total of 75 taxa were recorded belonging to 37 families and 53 genera. The majority of the macrophytes belonged to coastal plants (76%), whereas the rest of the macrophytes belonged to aquatic plants (24%). Species of the family Asteraceae were dominant among coastal plants, whereas species of the family Potamogetonaceae were dominant among aquatic plants. Soil samples from the site of Dam of Veria had higher pH and electric conductivity (80-100 cm depth), whereas CaCO3 contents were significantly higher in soil samples from the area of P. Prodromos (60-80 cm depth). Most physicochemical water parameters as well as selected soil nutrients and major ionic components showed an increase during the low charge period (fall) compared to with the high charge period (spring), especially in parameters associated with agricultural activity. Furthermore, there was an increase in most examined values moving towards the delta of the river.
Spontaneous perforation of solitary ulcer of transverse colon
Galanis Ioannis,Dragoumis Dimitrios,Kalogirou Thomas,Lakis Sotiris
Indian Journal of Pathology and Microbiology , 2010,
Abstract: Spontaneous ruptures of the colon and rectum are extremely uncommon clinical entities and always require laparotomy. A 44-year-old female was admitted with a 12-hour history of severe abdominal pain periumbilically and at the right hypochondrium. The patient was immediately transferred to the department of surgery for close surgical observation. Computed tomography (CT) of the entire abdomen performed just before the operation demonstrated thickening of the wall of the ascending colon with pericolic fat stranding. Surgery revealed a perforation at the antimesenteric wall of the transverse colon and segmental colectomy of the transverse colon was performed. The histological evaluation demonstrated a perforated solitary ulcer of the transverse colon. There are only few known etiologic factors concerning spontaneous ruptures of the colon and rectum and usually none of these causative factors can easily be recognised. Their clinical appearance is most of the times acute abdomen and, despite the use of all appropriate diagnostic methods, the diagnosis is usually set postoperatively.
AMACR is associated with advanced pathologic risk factors in sporadic colorectal adenomas
Sotiris Lakis, Theodora Papamitsou, Constantina Panagiotopoulou, Rodoula Kotakidou, Vassiliki Kotoula
World Journal of Gastroenterology , 2010,
Abstract: AIM: To analyze α-methylacyl CoA racemase (AMACR) expression in relation to various dysplasia phenotypes and clinicopathological parameters of sporadic colorectal adenomas.METHODS: Fifty-five cases of sporadic colorectal adenomas were categorized according to the Vienna classification for Gastrointestinal Neoplasia. These corresponded to a total of 98 different intra-lesion microscopic fields that were further independently assigned a histological grade based on the old nomenclature (mild, moderate, severe dyplasia and carcinoma in situ). AMACR expression was evaluated by immunohistochemistry and statistical analysis was performed to investigate possible associations with various clinicopathologic parameters of adenomas i.e. gender, age, localization, grade of dysplasia, size and configuration.RESULTS: Patient age ranged from 41 to 84 years (mean 65 ± 13.2 years); 37 patients were males and 18 were females. Adenomas ranged in size between 0.5 and 30 cm (mean 2 ± 1.3 cm), including 18 tubular, 16 villous, 20 mixed or tubulovillous, and 1 giant sessile villous adenoma. AMACR expression was observed in 3 out of 16 (18.8%) of low-grade vs 23 out of 35 (62.8%) of high-grade lesions (P = 0.002). Most adenomas exhibiting high grade dysplasia with in situ carcinoma-like areas stained positive for AMACR (15/17 or 88.2%) as compared to adenomas with high grade dysplasia which contained severe dysplasia-like foci (6/15 or 40%), (P = 0.005). In AMACR positive adenomas featuring severe dysplasia-like or in situ carcinoma-like areas, AMACR staining was not necessarily observed in the in situ component. Positivity in intra-lesion of mild, moderate or severe dysplasia-like foci was more often encountered in adenomas harboring in situ, intramucosal or infiltrative carcinoma [21/33 (63.6%) vs 9/40 (22.5%), P < 0.001]. Strong AMACR expression was found in 11 out of 17 villous adenomas, but in only 1 out of 18 tubular lesions (P = 0.005). Larger lesions, i.e. > 1 cm stained more frequently for AMACR than smaller ones [27/45 (60%) vs 2/10 (20%), P = 0.02]. Overall, AMACR expression was associated with the grade of dysplasia, as well as with the size and configuration of adenomas, i.e. the consensus risk factors applied to colorectal adenoma patient surveillance.CONCLUSION: It may be worthy to further evaluate the possible use of AMACR as an additional risk factor for the assessment of colorectal adenoma patients.
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