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OBJECTIVE: This study determined the clinical utility of an fMRI classification algorithm predicting medication-class of response in patients with challenging mood diagnoses. METHODS: Ninety-nine 16-27-year-olds underwent resting state fMRI scans in three groups-BD, MDD and healthy controls. A predictive algorithm was trained and cross-validated on the known-diagnosis patients using maximally spatially independent components (ICs), constructing a similarity matrix among subjects, partitioning the matrix in kernel space and optimizing support vector machine classifiers and IC combinations. This classifier was also applied to each of 12 new individual patients with unclear mood disorder diagnoses. RESULTS: Classification within the known-diagnosis group was approximately 92.4% accurate. The five maximally contributory ICs were identified. Applied to the complicated patients, the algorithm diagnosis was consistent with optimal medication-class of response to sustained recovery in 11 of 12 cases (i.e., almost 92% accuracy). CONCLUSION: This classification algorithm performed well for the know-diagnosis but also predicted medication-class of response in difficult-to-diagnose patients. Further research can enhance this approach and extend these findings to be more clinically accessible.
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Transtorno Bipolar/diagnóstico por imagem , Conectoma/métodos , Transtorno Depressivo Maior/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Máquina de Vetores de Suporte , Adolescente , Adulto , Transtorno Bipolar/classificação , Transtorno Depressivo Maior/classificação , Diagnóstico Diferencial , Feminino , Humanos , Imageamento por Ressonância Magnética , Adulto JovemRESUMO
Understanding magnetic phases in quantum mechanical systems is one of the essential goals in condensed matter physics, and the advent of prototype quantum simulation hardware has provided new tools for experimentally probing such systems. We report on the experimental realization of a quantum simulation of interacting Ising spins on three-dimensional cubic lattices up to dimensions 8 × 8 × 8 on a D-Wave processor (D-Wave Systems, Burnaby, Canada). The ability to control and read out the state of individual spins provides direct access to several order parameters, which we used to determine the lattice's magnetic phases as well as critical disorder and one of its universal exponents. By tuning the degree of disorder and effective transverse magnetic field, we observed phase transitions between a paramagnetic, an antiferromagnetic, and a spin-glass phase.
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OBJECTIVE: Marijuana (MJ) use is common. Research shows risks for psychiatric illnesses, including major depressive disorder (MDD) and cognitive deficits with MJ use, particularly early-onset use. We investigated cognitive function, functional connectivity, and genetic risk with MDD alone and combined with MJ use, and differences between early-vs. late-onset/non-MJ use in youth. METHOD: A total of 74 youth in four groups were studied: healthy control, MDD, frequent MJ use and current/past MDD plus frequent MJ use. Psychiatric symptoms, cognitive performance and demographics were measured. Default mode network (DMN) brain connectivity was determined. Risk alleles in six genes of interest were evaluated. RESULTS: DMN differences among groups in reward-processing and motor control regions were found; the effects of MJ use and MDD were distinct. Early-onset MJ use was associated with lower IQ and hyperconnectivity within areas of the DMN. Early-onset MJ use was associated with the BDNF risk allele. CONCLUSIONS: Cognitive deficits linked with early-onset MJ use were present within several years after MJ use began and may result from, predispose to, or share a common cause with early-onset MJ use. The DMN was affected by MDD, MJ and their combination, as well as by early-onset MJ use. BDNF carrier state may predispose to early-onset MJ use.
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Fator Neurotrófico Derivado do Encéfalo/genética , Transtornos Cognitivos/induzido quimicamente , Transtorno Depressivo Maior/fisiopatologia , Abuso de Maconha/fisiopatologia , Adolescente , Idade de Início , Mapeamento Encefálico/métodos , Transtornos Cognitivos/genética , Transtorno Depressivo Maior/genética , Imagem de Difusão por Ressonância Magnética , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Abuso de Maconha/genética , Abuso de Maconha/psicologia , Adulto JovemRESUMO
Exposure to psychological trauma (for example, childhood/early life adversity, exposure to violence or assault, combat exposure, accidents or natural disasters) is known to increase one's risk of developing certain chronic medical conditions. Clinical and population studies provide evidence of systemic inflammatory activity in trauma survivors with various psychiatric and nonpsychiatric conditions. This transdiagnostic meta-analysis quantitatively integrates the literature on the relationship of inflammatory biomarkers to trauma exposure and related symptomatology. We conducted random effects meta-analyses relating trauma exposure to log-transformed inflammatory biomarker concentrations, using meta-regression models to test the effects of study quality and psychiatric symptomatology on the inflammatory outcomes. Across k=36 independent samples and n=14,991 participants, trauma exposure was positively associated with C-reactive protein (CRP), interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α (mean rs =0.2455, 0.3067, 0.2890, and 0.2998, respectively). No significant relationships were noted with fibrinogen, IL-2, IL-4, IL-8, or IL-10. In meta-regression models, the presence of psychiatric symptoms was a significant predictor of increased effect sizes for IL-1ß and IL-6 (ß=1.0175 and 0.3568, respectively), whereas study quality assessment scores were associated with increased effect sizes for IL-6 (ß=0.3812). Positive correlations between inflammation and trauma exposure across a range of sample types and diagnoses were found. Although reviewed studies spanned an array of populations, research on any one specific psychiatric diagnosis was generally limited to one or two studies. The results suggest that chronic inflammation likely represents one potential mechanism underlying risk of health problems in trauma survivors.
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Proteína C-Reativa , Citocinas , Inflamação/imunologia , Acontecimentos que Mudam a Vida , Transtornos de Estresse Traumático/imunologia , Sobreviventes , HumanosRESUMO
The encapsulation of therapeutic cells permits the implantation of allogeneic and xenogeneic cells for the regulation of certain physiological processes damaged by the death or senescence of host tissues. The encapsulation of pancreatic cells for the treatment of diabetes is emphasized; however, many of the techniques are applicable to a wide array of mammalian cell applications. The summary of both established and novel encapsulation techniques, clinical trials, and commercial product developments highlights the metered but steady pace of therapeutic cell encapsulation towards implementation.
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Diabetes Mellitus Tipo 1/cirurgia , Transplante das Ilhotas Pancreáticas/métodos , Alginatos/química , Animais , Emulsões , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Pâncreas/anatomia & histologia , Transplante de Pâncreas , Eletricidade Estática , Alicerces TeciduaisRESUMO
Efforts to develop useful quantum computers have been blocked primarily by environmental noise. Quantum annealing is a scheme of quantum computation that is predicted to be more robust against noise, because despite the thermal environment mixing the system's state in the energy basis, the system partially retains coherence in the computational basis, and hence is able to establish well-defined eigenstates. Here we examine the environment's effect on quantum annealing using 16 qubits of a superconducting quantum processor. For a problem instance with an isolated small-gap anticrossing between the lowest two energy levels, we experimentally demonstrate that, even with annealing times eight orders of magnitude longer than the predicted single-qubit decoherence time, the probabilities of performing a successful computation are similar to those expected for a fully coherent system. Moreover, for the problem studied, we show that quantum annealing can take advantage of a thermal environment to achieve a speedup factor of up to 1,000 over a closed system.
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Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of Z0/γ*-tagged jet events in sqrt[s]=2.76 TeV reactions at the LHC. Our results combine the O(G(F)α(s)2) perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense strongly interacting matter. We find that a strong asymmetry is generated in central lead-lead reactions that has little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for its shape and magnitude.
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Encapsulation of therapeutic peptides and proteins into polymeric micro and nanoparticulates has been proposed as a strategy to overcome limitations to oral protein administration. Particles having diameter less than 5 µm are able to be taken up by the M cells of Peyer's patches found in intestinal mucosa. Current formulation methodologies involve organic solvents and several time consuming steps. In this study, spray drying was investigated to produce protein loaded micro/nanoparticles, as it offers the potential for single step operation, producing dry active-loaded particles within the micro to nano-range. Spherical, smooth surfaced particles were produced from alginate/protein feed solutions. The effect of operational parameters on particle properties such as recovery, residual activity and particle size was studied using subtilisin as model protein. Particle recovery depended on the inlet temperature of the drying air, and mean particle size ranged from 2.2 to 4.5 µm, affected by the feed rate and the alginate concentration in the feed solution. Increase in alginate:protein ratio increased protein stability. Presence of 0.2 g trehalose/g particle increased the residual activity up to 90%. Glycol-chitosan-Ca(2+)alginate particles were produced in a single step operation, with resulting mean diameter of 3.5 µm. Particles showed fluorescein isothiocyanate labeled bovine serum albumin (BSA)-protein entrapment with increasing concentration toward the particle surface. Similar, limited release profiles of BSA, subtilisin and lysozyme were observed in gastric simulation, with ultimate full release of the proteins in gastrointestinal simulation.
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Alginatos/química , Quitosana/química , Portadores de Fármacos/química , Soroalbumina Bovina/química , Cálcio/química , Excipientes/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microesferas , Muramidase/administração & dosagem , Muramidase/química , Nanopartículas , Tamanho da Partícula , Estabilidade Proteica , Soroalbumina Bovina/administração & dosagem , Subtilisina/administração & dosagem , Subtilisina/química , Temperatura , Trealose/químicaRESUMO
BACKGROUND: Current theories of post-traumatic stress disorder (PTSD) place considerable emphasis on the role cognitive distortions such as self-blame, hopelessness or preoccupation with danger play in the etiology and maintenance of the disorder. Previous studies have shown that cognitive distortions in the early aftermath of traumatic events can predict future PTSD severity but, to date, no studies have investigated the neural correlates of this association. METHOD: We conducted a prospective study with 106 acutely traumatized subjects, assessing symptom severity at three time points within the first 3 months post-trauma. A subsample of 20 subjects additionally underwent a functional 4-T magnetic resonance imaging (MRI) scan at 2 to 4 months post-trauma. RESULTS: Cognitive distortions proved to be a significant predictor of concurrent symptom severity in addition to diagnostic status, but did not predict future symptom severity or diagnostic status over and above the initial symptom severity. Cognitive distortions were correlated with blood oxygen level-dependent (BOLD) signal strength in brain regions previously implicated in visual processing, imagery and autobiographic memory recall. Intrusion characteristics accounted for most of these correlations. CONCLUSIONS: This investigation revealed significant predictive value of cognitive distortions concerning concurrent PTSD severity and also established a significant relationship between cognitive distortions and neural activations during trauma recall in an acutely traumatized sample. These data indicate a direct link between the extent of cognitive distortions and the intrusive nature of trauma memories.
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Transtornos Cognitivos/psicologia , Transtornos de Estresse Pós-Traumáticos/complicações , Transtornos de Estresse Pós-Traumáticos/psicologia , Adulto , Idoso , Encéfalo/patologia , Transtornos Cognitivos/complicações , Transtornos Cognitivos/patologia , Feminino , Humanos , Entrevista Psicológica , Modelos Logísticos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Ontário , Estudos Prospectivos , Índice de Gravidade de Doença , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Adulto JovemRESUMO
OBJECTIVE: The goal of this study was to investigate the relationship between default mode network connectivity and the severity of post-traumatic stress disorder (PTSD) symptoms in a sample of eleven acutely traumatized subjects. METHOD: Participants underwent a 5.5 min resting functional magnetic resonance imaging scan. Brain areas whose activity positively correlated with that of the posterior cingulate/precuneus (PCC) were assessed. To assess the relationship between severity of PTSD symptoms and PCC connectivity, the contrast image representing areas positively correlated with the PCC was correlated with the subjects' Clinician Administered PTSD Scale scores. RESULTS: Results suggest that resting state connectivity of the PCC with the perigenual anterior cingulate and the right amygdala is associated with current PTSD symptoms and that correlation with the right amygdala predicts future PTSD symptoms. CONCLUSION: These results may contribute to the development of prognostic tools to distinguish between those who will and those who will not develop PTSD.
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Tonsila do Cerebelo/fisiopatologia , Giro do Cíngulo/fisiopatologia , Acontecimentos que Mudam a Vida , Imageamento por Ressonância Magnética/estatística & dados numéricos , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Feminino , Lateralidade Funcional/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Vias Neurais/fisiopatologia , Probabilidade , Prognóstico , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Descanso/fisiologia , Índice de Gravidade de DoençaRESUMO
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
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Alginate nanoparticles were prepared from dilute alginate sol by inducing a pre-gel with calcium counter ions, followed by polyelectrolyte complex coating with chitosan. Particles in the nanometer size range were obtained with 0.05% alginate and 0.9 mM Ca2+. The mean particle size was influenced by time and stirring speed of nanoparticle preparation, by alginate guluronic acid content and chitosan molecular weight and by the initial alginate:chitosan mass ratio. The association efficiency of insulin into alginate nanoparticles, as well as loading capacity were mainly influenced by the alginate:chitosan mass ratio. Under optimized size conditions, the association efficiency and loading capacities were as high as 92% and 14.3%, respectively. Approximately 50% of the protein was partially retained by the nanoparticles in gastric pH environment up to 24 hours while a more extensive release close to 75% was observed under intestinal pH conditions. Mild formulation conditions, optimum particle size range obtained, high insulin entrapment efficiency, and resistance to gastrointestinal release seem to be synergic and promising factors toward development of an oral insulin delivery form.
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Alginatos/química , Quitosana/química , Eletrólitos/química , Insulina/metabolismo , Nanocompostos/química , Nanopartículas/química , Acetatos/química , Cálcio/química , Cloreto de Cálcio/química , Sistemas de Liberação de Medicamentos , Géis , Concentração de Íons de Hidrogênio , Insulina/química , Íons , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Polímeros/químicaRESUMO
Spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (MRI) signal have been shown to reflect neural synchrony between brain regions. A "default network" of spontaneous low-frequency fluctuations has been described in healthy volunteers during stimulus-independent thought. Negatively correlated with this network are regions activated during attention-demanding tasks. Both these networks involve brain regions and functions that have been linked with schizophrenia in previous research. The present study examined spontaneous slow fluctuations in the BOLD signal at rest, as measured by correlation with low-frequency oscillations in the posterior cingulate, in 17 schizophrenic patients, and 17 comparable healthy volunteers. Healthy volunteers demonstrated correlation between spontaneous low-frequency fluctuations of the BOLD signal in the posterior cingulate and fluctuations in the lateral parietal, medial prefrontal, and cerebellar regions, similar to previous reports. Schizophrenic patients had significantly less correlation between spontaneous slow activity in the posterior cingulate and that in the lateral parietal, medial prefrontal, and cerebellar regions. Connectivity of the posterior cingulate was found to vary with both positive and negative symptoms in schizophrenic patients. Because these data suggest significant abnormalities in resting-state neural networks in schizophrenia, further investigations of spontaneous slow fluctuations of the BOLD signal seem warranted in this population.
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Rede Nervosa/fisiopatologia , Esquizofrenia/fisiopatologia , Transdução de Sinais/fisiologia , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/fisiopatologia , Circulação Cerebrovascular/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Giro do Cíngulo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Oxigênio/sangueRESUMO
PURPOSE: To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats. METHODS: Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by confocal microscopy. RESULTS: Nanoparticles were negatively charged and had a mean size of 750 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. The insulin association efficiency was over 70% and insulin was released in a pH-dependent manner under simulated gastrointestinal conditions. Orally delivered nanoparticles lowered basal serum glucose levels by more than 40% with 50 and 100 IU/kg doses sustaining hypoglycemia for over 18 h. Pharmacological availability was 6.8 and 3.4% for the 50 and 100 IU/kg doses respectively, a significant increase over 1.6%, determined for oral insulin alone in solution and over other related studies at the same dose levels. Confocal microscopic examinations of FITC-labelled insulin nanoparticles showed clear adhesion to rat intestinal epithelium, and internalization of insulin within the intestinal mucosa. CONCLUSION: The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity.
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Alginatos/química , Glicemia/efeitos dos fármacos , Quitosana/química , Diabetes Mellitus Experimental/tratamento farmacológico , Portadores de Fármacos , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Nanopartículas , Administração Oral , Animais , Disponibilidade Biológica , Química Farmacêutica , Diabetes Mellitus Experimental/sangue , Relação Dose-Resposta a Droga , Composição de Medicamentos , Fluoresceína-5-Isotiocianato/análogos & derivados , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Insulina/administração & dosagem , Insulina/análogos & derivados , Insulina/química , Insulina/farmacocinética , Absorção Intestinal , Mucosa Intestinal/metabolismo , Masculino , Microscopia Confocal , Tamanho da Partícula , Ratos , Ratos Wistar , SolubilidadeRESUMO
OBJECTIVE: This study used functional connectivity analyses to assess interregional brain activity correlations during the recall of traumatic memories in traumatized subjects with and without posttraumatic stress disorder (PTSD). METHOD: Both 4-T functional magnetic resonance imaging (fMRI) and functional connectivity analyses were used to assess interregional brain activity correlations during script-driven symptom provocation in traumatized subjects with (N=11) and without (N=13) PTSD. Functional connectivity analyses were carried out by using data for brain regions activated in both the PTSD group and the comparison group. The use of functional connectivity analyses in addition to subtraction analyses allowed assessment of specific brain regions involved in the recall of traumatic events and of the neuronal networks underlying the recall of such events. RESULTS: Significant between-group differences in functional connectivity were found. Comparison of connectivity maps at coordinates x=2, y=20, z=36 (right anterior cingulate gyrus) for the two groups showed that the subjects without PTSD had greater correlation than the PTSD subjects in the left superior frontal gyrus (Brodmann's area 9), left anterior cingulate gyrus (Brodmann's area 32), left striatum (caudate), left parietal lobe (Brodmann's areas 40 and 43), and left insula (Brodmann's area 13). In contrast, the PTSD subjects showed greater correlation than the subjects without PTSD in the right posterior cingulate gyrus (Brodmann's area 29), right caudate, right parietal lobe (Brodmann's areas 7 and 40), and right occipital lobe (Brodmann's area 19). CONCLUSIONS: The differences in brain connectivity between PTSD and comparison subjects may account for the nonverbal nature of traumatic memory recall in PTSD subjects, compared to a more verbal pattern of traumatic memory recall in comparison subjects.
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Encéfalo/metabolismo , Encéfalo/fisiopatologia , Imaginação , Imageamento por Ressonância Magnética , Rede Nervosa/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Encéfalo/anatomia & histologia , Humanos , Interpretação de Imagem Assistida por Computador , Rememoração Mental/fisiologia , Índice de Gravidade de Doença , Transtornos de Estresse Pós-Traumáticos/psicologia , Técnica de SubtraçãoRESUMO
OBJECTIVE: To describe the development of the Thought Disorder Questionnaire (TDQ), including data on reliability and validity, and to explain the questionnaire's feasibility and diagnostic accuracy. METHODS: The TDQ has 6 scales, each with 10 items (on a scale from 0 [for never] to 4 [for always]). The 6 scales measure content of thought, control of thought, orientation, perception, fantasy, and symptoms. RESULTS: The TDQ is a reliable 60-item, self-report questionnaire that measures the quantity and quality of disordered thinking in patients with mental disorders. It has established reliability and validity. CONCLUSION: The TDQ's clinical and research utility remains to be determined.
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Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Transtornos Psicóticos/psicologia , Inquéritos e Questionários , Pensamento , Estudos de Viabilidade , Humanos , Reprodutibilidade dos TestesRESUMO
Vulnerability-stress models suggest that training in specific stress management techniques should yield benefits to those suffering from schizophrenia and related disorders. In this paper, we describe an evaluation of the impact of adding a stress management program to other medical and psychosocial interventions for such patients. Outcomes were compared for 121 patients randomly assigned to receive either a 12-week stress management program with follow-up sessions or participation in a social activities group. The two treatment conditions did not differ in levels of symptoms, perceived stress or life skills immediately after completion of treatment or at 1-year follow-up. Patients who received the stress management program did have fewer hospital admissions in the year following treatment. This effect of stress management was most apparent for those who showed high levels of attendance for treatment sessions. It was concluded that training in stress management may provide patients with skills for coping with acute stressors and reduce the likelihood of subsequent acute exacerbation of symptoms with need for hospitalization.
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Psicoterapia/métodos , Esquizofrenia , Psicologia do Esquizofrênico , Estresse Psicológico/psicologia , Estresse Psicológico/terapia , Adaptação Psicológica , Adulto , Análise Fatorial , Feminino , Seguimentos , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Resolução de Problemas , Avaliação de Programas e Projetos de Saúde , Distribuição Aleatória , Esquizofrenia/reabilitaçãoRESUMO
OBJECTIVE: The neuronal circuitry underlying posttraumatic stress disorder (PTSD) was studied in traumatized subjects with and without PTSD. METHOD: Traumatized subjects with (N=9) and without (N=9) PTSD were studied by using the script-driven symptom provocation paradigm adapted to functional magnetic resonance imaging at a 4-T field strength. RESULTS: PTSD subjects showed significantly less activation of the thalamus, the anterior cingulate gyrus (Brodmann's area 32), and the medial frontal gyrus (Brodmann's area 10/11) than did the comparison subjects. CONCLUSIONS: The findings suggest anterior cingulate, frontal, and thalamic involvement in the neuronal circuitry underlying PTSD.
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Encéfalo/anatomia & histologia , Encéfalo/fisiopatologia , Imageamento por Ressonância Magnética , Memória , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Comorbidade , Transtorno Depressivo Maior/epidemiologia , Transtorno Distímico/epidemiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Transtorno de Pânico/epidemiologia , Prevalência , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/epidemiologiaRESUMO
Tannase was encapsulated in alginate, chitosan, carrageenan or pectin gel matrices, and in the case of alginate, coated with high or low molecular weight chitosan to reduce enzyme release. Cross-linking with glutaraldehyde also improved enzyme retention. Active enzyme preparations were obtained, although carrageenan gels were unstable in tea. Tannase activity was evaluated by reduction in centrifugable (flocculated) tea solids, and a reduction in tea cream measured turbidimetrically after removal of flocculated solids. Tannin interactions with the polysaccharide gels increased the level of centrifugable solids (flocculent) in the tea. An optimum bead formulation consisted of an alginate core, coated with chitosan and cross-linked with glutaraldehyde. Both core and coating materials contained active enzyme. Beads were prepared in a single step procedure involving extrusion of alginate/tannase solution into a hardening bath containing tannase-loaded, chitosan solution. Tannase retained hydrolytic activity through three successive batch cycles, for a total period of 39h processing, and tea cream was visibly removed by treatment with the immobilized tannase. Activity remained stable during 1-month bead storage under refrigeration.
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The relationships of serum lipids with Alzheimer's disease (AD) and other dementias in very old patients are not clear. All residents of an academic nursing home were studied clinically for dementia and for serum lipids. All those autopsied over a 7.7-year period had apolipoprotein E (apoE) genotyping and detailed neuropathological examination. Those with pathologically defined criteria for AD (n = 84) were compared to all others who also had clinical dementia but did not show AD changes (n = 22). In contrast to most other reports of serum lipids in very old patients with AD, total cholesterol (TC) and low density lipoprotein cholesterol levels were each significantly higher for those with AD. The lipid-AD associations were progressively stronger with increasing pathological certainty of AD diagnosis. These relationships remained significant after adjustment for apoE genotype and for other known risk factors. The lipid-AD associations in a very old cohort, and prior evidence that elevated TC in middle life is a risk factor for later dementia, prompt consideration of factors associated with lipid metabolism in the development of Alzheimer's dementia.