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1.
J Small Anim Pract ; 65(6): 402-408, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38566458

RESUMO

OBJECTIVES: Myoclonic seizures are considered a type of generalised seizure characterised by brief, jerking movements of the body. The aim of this study is to describe cases of suspected canine myoclonic seizure of idiopathic aetiology and to discuss the successful use of the anticonvulsant levetiracetam as treatment in each of these cases. MATERIALS AND METHODS: Dogs with epileptic myoclonus suspected to be idiopathic in aetiology were considered for inclusion. Medical records were reviewed for physical and neurologic examination findings, clinicopathologic results, and diagnostic imaging results. All included dogs were treated with levetiracetam, and their response was reported. RESULTS: Five dogs were included, all of which had suspected myoclonic seizures either observed in-person or on video recording by a board-certified veterinary neurologist. The duration of myoclonic seizures preceding treatment ranged from one day to one year. One dog also experienced a generalised tonic-clonic seizure. All dogs were treated with levetiracetam. Two dogs experienced long-term myoclonic seizure freedom (duration seizure-free of at least 1 year), and two dogs experienced marked decreased myoclonic seizure frequency. One dog experienced immediate abatement of myoclonic seizures, although levetiracetam was only utilised for 1 month following onset of myoclonic seizures in this patient. CLINICAL SIGNIFICANCE: Myoclonic seizures can be idiopathic in aetiology. Levetiracetam can be used effectively to rapidly stop myoclonic seizures and to decrease the frequency of myoclonic seizures.


Assuntos
Anticonvulsivantes , Doenças do Cão , Epilepsias Mioclônicas , Levetiracetam , Cães , Levetiracetam/uso terapêutico , Animais , Anticonvulsivantes/uso terapêutico , Doenças do Cão/tratamento farmacológico , Feminino , Masculino , Epilepsias Mioclônicas/veterinária , Epilepsias Mioclônicas/tratamento farmacológico , Resultado do Tratamento
2.
Acta Neurol Scand ; 137(1): 91-98, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28869277

RESUMO

OBJECTIVES: Cognitive decline is common in Parkinson's disease (PD), but the underlying mechanisms for this complication are incompletely understood. Genotypes affecting dopamine transmission may be of importance. This study investigates whether genotypes associated with reduced prefrontal dopaminergic tone and/or reduced dopamine D2-receptor availability (Catechol-O-methyltransferase [COMT] Val158 Met genotype and DRD2 C957 T genotype) affect the development of cognitive deficits in PD. MATERIALS AND METHODS: One hundred and 34 patients with idiopathic PD, participating in a regional, population-based study of incident parkinsonism, underwent genotyping. After extensive baseline investigations (including imaging and biomarker analyses), the patients were followed prospectively during 6-10 years with neuropsychological evaluations, covering six cognitive domains. Cognitive decline (defined as the incidence of either Parkinson's disease mild cognitive impairment [PD-MCI] or dementia [PDD], diagnosed according to published criteria and blinded to genotype) was studied as the primary outcome. RESULTS: Both genotypes affected cognition, as shown by Cox proportional hazards models. While the COMT 158 Val/Val genotype conferred an increased risk of mild cognitive impairment in patients with normal cognition at baseline (hazard ratio: 2.13, P = .023), the DRD2 957 T/T genotype conferred an overall increased risk of PD dementia (hazard ratio: 3.22, P < .001). The poorer cognitive performance in DRD2 957 T/T carriers with PD occurred mainly in episodic memory and attention. CONCLUSIONS: The results favor the hypothesis that dopamine deficiency in PD not only relate to mild cognitive deficits in frontostriatal functions, but also to a decline in memory and attention. This could indicate that dopamine deficiency impairs a wide network of brain areas.


Assuntos
Catecol O-Metiltransferase/genética , Disfunção Cognitiva/genética , Doença de Parkinson/genética , Receptores de Dopamina D2/genética , Idoso , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Doença de Parkinson/complicações , Polimorfismo de Nucleotídeo Único
4.
Nat Commun ; 8: 14024, 2017 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-28102222

RESUMO

Electron pairing in the vast majority of superconductors follows the Bardeen-Cooper-Schrieffer theory of superconductivity, which describes the condensation of electrons into pairs with antiparallel spins in a singlet state with an s-wave symmetry. Unconventional superconductivity was predicted in single-layer graphene (SLG), with the electrons pairing with a p-wave or chiral d-wave symmetry, depending on the position of the Fermi energy with respect to the Dirac point. By placing SLG on an electron-doped (non-chiral) d-wave superconductor and performing local scanning tunnelling microscopy and spectroscopy, here we show evidence for a p-wave triggered superconducting density of states in SLG. The realization of unconventional superconductivity in SLG offers an exciting new route for the development of p-wave superconductivity using two-dimensional materials with transition temperatures above 4.2 K.

5.
Sci Rep ; 7: 40604, 2017 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-28106102

RESUMO

Spin filter superconducting S/I/N tunnel junctions (NbN/GdN/TiN) show a robust and pronounced Zero Bias Conductance Peak (ZBCP) at low temperatures, the magnitude of which is several times the normal state conductance of the junction. Such a conductance anomaly is representative of unconventional superconductivity and is interpreted as a direct signature of an odd frequency superconducting order.

6.
Nat Commun ; 6: 8053, 2015 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-26329811

RESUMO

The theory of superconductivity developed by Bardeen, Cooper and Schrieffer (BCS) explains the stabilization of electron pairs into a spin-singlet, even frequency, state by the formation of an energy gap within which the density of states is zero. At a superconductor interface with an inhomogeneous ferromagnet, a gapless odd frequency superconducting state is predicted, in which the Cooper pairs are in a spin-triplet state. Although indirect evidence for such a state has been obtained, the gap structure and pairing symmetry have not so far been determined. Here we report scanning tunnelling spectroscopy of Nb superconducting films proximity coupled to epitaxial Ho. These measurements reveal pronounced changes to the Nb subgap superconducting density of states on driving the Ho through a metamagnetic transition from a helical antiferromagnetic to a homogeneous ferromagnetic state for which a BCS-like gap is recovered. The results prove odd frequency spin-triplet superconductivity at superconductor/inhomogeneous magnet interfaces.

7.
Ann Dermatol Venereol ; 142(5): 332-9, 2015 May.
Artigo em Francês | MEDLINE | ID: mdl-25846467

RESUMO

BACKGROUND: Acute ischemia of the upper limbs is rare in comparison with ischemia of the lower limbs. The origins of this condition are varied. GOALS: We retrospectively analyzed cases of acute finger ischemia (Raynaud's phenomena was excluded) in a dermatology department between 2008 and 2013 in order to evaluate the etiology and management of this phenomenon. RESULTS: Thirteen cases of finger ischemia were reported. The mean age was 54 years. Active smoking was noted in 11 cases. Ischemia was acute in 9 cases and subacute in 4 cases. The location was unilateral in 10 cases and bilateral in 2. Etiologies were: dysplasia of the palmar arch, antiphospholipid antibody syndrome, frostbite, distal arteritis linked to smoking, paraneoplastic arteritis, Buerger's disease, polyarteritis nodosa, stenosis of the subclavian artery, and 3 cases of embolic origin (ulnar, cardiac, and paraneoplastic aneurysm). In the acute phase, antiplatelets were given in 6 cases, anticoagulants in 10 cases and ilomedin in 6 cases. Sympathectomy was performed in 1 case and amputation in 2 cases. DISCUSSION: This study illustrates the diversity of etiologies of finger ischemia. The etiological test battery should be broad and include immunological and thrombophilia tests, arterial and cardiac investigations, cervical radiography and CT scan (screening for cancer). Close collaboration between dermatologists, hematologists, vascular surgeons and radiologists is essential for the management of these patients.


Assuntos
Dedos/irrigação sanguínea , Isquemia/etiologia , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Amputação Cirúrgica , Síndrome Antifosfolipídica , Arterite/complicações , Feminino , Dedos/cirurgia , Congelamento das Extremidades/complicações , Humanos , Isquemia/terapia , Masculino , Pessoa de Meia-Idade , Síndromes Paraneoplásicas/complicações , Inibidores da Agregação Plaquetária/uso terapêutico , Poliarterite Nodosa/complicações , Estudos Retrospectivos , Fumar/efeitos adversos , Síndrome do Roubo Subclávio/complicações , Simpatectomia , Tromboangiite Obliterante/complicações
8.
Asia Pac J Oncol Nurs ; 2(3): 186-191, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27981113

RESUMO

Breast cancer is the leading cause of cancer in females between the ages of 15 and 54, and the second leading cause of cancer death in women in the United States. Diagnosis begins with detection by breast examination (clinical breast exam or breast self-exam) or by radiologic studies, like mammography. Many advances in the diagnosis of breast cancer have taken place in recent years. This article will review the history of radiologic advances in the diagnosis of breast cancer. Use of technological advancements in digital breast tomosynthesis, magnetic resonance imaging, and ultrasound in breast cancer diagnosis will be presented. Advantages and disadvantages of these diagnostic interventions when compared to older, traditional X-ray films will be discussed. It is important for all nurses, including radiology and oncology nurses, to be well informed about these varied diagnostic modalities, and appreciate the fact that advances in radiologic imaging technologies can yield improved outcomes for breast cancer patients.

9.
Ann Dermatol Venereol ; 141(11): 682-4, 2014 Nov.
Artigo em Francês | MEDLINE | ID: mdl-25442472

RESUMO

BACKGROUND: Herein we report a case of phlegmasia cerulea dolens, a form of venous thrombosis complicated by arterial ischaemia. PATIENTS AND METHODS: A 69-year-old man presented a bilateral trophic condition of the lower limbs that had appeared 3 weeks earlier. The patient had a history of metastatic urothelial bladder carcinoma and arteritis. Clinical examination revealed right leg ulcers with massive bilateral oedema of the lower limbs, cyanosis and local ischaemia. Doppler ultrasound revealed bilateral and proximal deep vein thrombosis (sural and superficial femoral veins of the right leg; sural and iliac veins of the left leg) without any distal arterial flow. We concluded on a diagnosis of bilateral phlegmasia cerulea dolens. DISCUSSION: Phlegmasia cerulea dolens is a particular type of deep venous thrombosis in which a proximal venous thrombus is combined with arterial ischaemic signs due to brutal and massive oedema and slowing down of arterial flow. In most cases, the lower limbs are involved, with malignancy being the most common cause. It should be suspected in the presence of the classical triad of "pain, oedema and cyanosis", with confirmation by Doppler ultrasound. There is no general consensus regarding standard management. Traditionally, systemic anticoagulation has been the mainstay of treatment for this condition. Endovascular surgery may be a possibility in some cases. Prompt diagnosis and rapid treatment initiation are paramount in order to improve the prognosis of this severe condition with ominous prospects.


Assuntos
Arterite/diagnóstico por imagem , Isquemia/diagnóstico por imagem , Perna (Membro)/irrigação sanguínea , Tromboflebite/diagnóstico por imagem , Trombose Venosa/diagnóstico por imagem , Idoso , Carcinoma/secundário , Carcinoma/cirurgia , Diagnóstico Diferencial , Edema/diagnóstico , Veia Femoral/diagnóstico por imagem , Humanos , Veia Ilíaca/diagnóstico por imagem , Úlcera da Perna/diagnóstico , Metástase Linfática/patologia , Masculino , Ultrassonografia Doppler/métodos , Neoplasias da Bexiga Urinária/cirurgia , Urotélio/patologia
10.
Acta Neurol Scand ; 130(1): 27-33, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24341730

RESUMO

OBJECTIVES: To investigate the effect of caudal zona incerta-deep brain stimulation (cZi-DBS) on word-level speech intelligibility in patients with Parkinson's disease, under both an optimal listening condition and a simulated more naturalistic listening condition. MATERIALS AND METHODS: Spoken single words were extracted from read samples collected from 10 bilaterally implanted patients with PD pre- and post-cZi-DBS. Intelligibility was assessed through a transcription task performed by 32 naive listeners under two listening conditions: (i) with low-amplitude conversational speech added as background and (ii) with no added background noise. The listeners' responses were scored in terms of agreement with the intended words. RESULTS: Post-operatively, the total intelligibility score was significantly lower when cZi stimulation was switched on compared with off, for both listening conditions (with and without added background noise). Intelligibility was also significantly lower on stimulation compared with preoperative recordings, but only when assessed in the listening condition without background noise. The listening condition with added background noise resulted in significantly lower intelligibility scores compared with the no added noise condition for all stimulation conditions. CONCLUSIONS: The results of this study indicate that cZi-DBS in patients with PD can be detrimental to word-level speech intelligibility.


Assuntos
Estimulação Encefálica Profunda/métodos , Doença de Parkinson/terapia , Inteligibilidade da Fala , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/complicações , Distúrbios da Fala/etiologia , Distúrbios da Fala/terapia , Zona Incerta/fisiologia
11.
Acta Neurol Scand ; 127(5): 329-36, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23116242

RESUMO

OBJECTIVE: In patients with Parkinson's disease (PD), deep brain stimulation of the subthalamic nucleus (STN DBS) is well recognized in improving limb function, but the outcome on swallowing function has rarely been studied. The aim of this work was to evaluate the effect of STN DBS on pharyngeal swallowing function in patients with PD using self-estimation and fiberoptic endoscopic evaluation of swallowing. METHODS: Eleven patients (aged 41-72, median 61 years) were evaluated preoperatively and at 6 and 12 months after STN DBS surgery. All patients were evaluated with self-estimation on a visual analogue scale, and eight of them with a fiberoptic endoscopic examination with a predefined swallowing protocol including Rosenbek's Penetration-Aspiration Scale, Secretion Severity Scale, preswallow spillage, pharyngeal residue, and pharyngeal clearance. RESULTS: The self-assessments of swallowing function revealed a subjective improvement with STN DBS stimulation, whereas the data from the swallowing protocol did not show any significant effect of the STN DBS treatment itself. The prevalence of aspiration was not affected by the surgery. CONCLUSIONS: The results show that swallowing function was not negatively affected by STN DBS and the risk of aspiration did not increase. Self-estimation of swallowing function showed a subjective improvement due to stimulation.


Assuntos
Estimulação Encefálica Profunda , Deglutição/fisiologia , Doença de Parkinson/terapia , Adulto , Idoso , Antiparkinsonianos/uso terapêutico , Terapia Combinada , Estimulação Encefálica Profunda/efeitos adversos , Autoavaliação Diagnóstica , Feminino , Humanos , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Doença de Parkinson/complicações , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/fisiopatologia , Pneumonia Aspirativa/etiologia , Pneumonia Aspirativa/prevenção & controle , Índice de Gravidade de Doença , Núcleo Subtalâmico/fisiopatologia
12.
Acta Neurol Scand ; 126(6): e29-33, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22690905

RESUMO

BACKGROUND: This interim 12-month analysis is a part of an open-label, observational, prospective study on health outcomes and cost impact of levodopa/carbidopa intestinal gel (LCIG, Duodopa) in Parkinson disease (PD). The specific aim was to investigate clinical and health-related quality of life (HRQoL) effects in routine care. METHODS: Unified PD rating scale (UPDRS) was the primary efficacy measurement. PD QoL questionnaire 39 (PDQ-39) assessed HRQoL. Subjects were assessed at baseline, ≥3 months after surgery, and then every 3 months. RESULTS: Twenty-seven treatment-naïve subjects when started with LCIG showed a decrease in UPDRS score that was statistically significant throughout the year: UPDRS total score (mean ± SD), baseline = 52.1 ± 16.1, N = 27, month 0 (first visit; at least 3 months after permanent LCIG) = 43.1 ± 16.7, N = 27, P = 0.003; month 12 = 42.5 ± 22.6, n = 25, P = 0.017. PDQ-39 results also showed a tendency for improvement: PDQ-39 (mean ± SD), baseline = 33.6 ± 10.8, N = 27, month 0 = 27.1 ± 11.8, N = 27, P = 0.001; 12 months = 28.8 ± 12.8, n = 23, P = 0.126. CONCLUSIONS: LCIG provides functional improvement beginning at first visit that is sustained for 12 months.


Assuntos
Antiparkinsonianos/administração & dosagem , Carbidopa/administração & dosagem , Levodopa/administração & dosagem , Doença de Parkinson/tratamento farmacológico , Vias de Administração de Medicamentos , Combinação de Medicamentos , Feminino , Humanos , Infusões Parenterais , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Resultado do Tratamento
13.
Acta Neurol Scand ; 126(5): 350-6, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22384826

RESUMO

OBJECTIVE: The purpose of the present study was to examine whether there was a negative effect of caudal Zona Incerta deep brain stimulation (cZI DBS) on pharyngeal swallowing function in Parkinson's patients (PD). There are no former reports including swallowing and cZI DBS. METHODS: Eight patients (aged 49-71 years; median 62) were evaluated pre- and post-operatively, at 6 and 12 months after DBS surgery. Evaluation tools were fiberoptic endoscopic evaluation of swallowing examinations and patients' self-assessments of their swallowing function including a visual analog scale and quality-of-life-related questions. The swallowing protocol included Rosenbek's Penetration-Aspiration Scale, Secretion Severity Scale and parameters for preswallow spillage, pharyngeal residue, and pharyngeal clearance. RESULTS: There was no clear-cut effect of neurostimulation post-operatively at 6 and 12 months on any of the swallowing parameters except for the preswallow spillage that was slightly worsened in the stimulation on condition 12 months post-operatively. The answers to the self assessment questions did not vary significantly. CONCLUSIONS: The effect of the stimulation on the swallowing function varied among individuals, but the overall outcome was that cZI DBS did not seem to have a negative influence on swallowing function in the eight patients studied.


Assuntos
Deglutição/fisiologia , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Subtálamo/fisiopatologia , Idoso , Estimulação Encefálica Profunda , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Acta Neurol Scand ; 126(4): 248-55, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22211900

RESUMO

OBJECTIVES: The differential diagnosis of patients with idiopathic parkinsonism is difficult, especially early in the course of the disease. External anal sphincter electromyography (EAS-EMG) has been reported to be of value in the differential diagnosis between Parkinson's disease (PD) and multiple system atrophy (MSA). Patients with MSA are reported to have pathological EAS-EMG and patients with PD are reported to have significantly less pathological EAS-EMG results. Comparisons between patients with parkinsonian disorders have usually been made many years into the disease, and thus it is largely unknown if the results of EAS-EMG can be used to distinguish the different diagnoses in the early phase of the disease. MATERIALS AND METHODS: We investigated 148 newly diagnosed patients with idiopathic parkinsonism from a population-based incidence cohort (100 definite PD, 21 probable PD, 16 MSA, 11 progressive supranuclear palsy, and 40 controls) with EAS-EMG within 3 months of their first visit and, in the majority of patients, before start of treatment with dopaminergic drugs. The clinical diagnoses were made using established clinical diagnostic criteria after a median follow-up of 3 years. RESULTS: All patient groups had more pathological EAS-EMG results than controls. No EAS-EMG differences were found between the patient groups, especially not between PD and MSA. CONCLUSIONS: External anal sphincter electromyography examination cannot separate the different parkinsonian subgroups from each other in early course of the diseases.


Assuntos
Canal Anal/patologia , Eletromiografia , Músculo Liso/fisiopatologia , Transtornos Parkinsonianos/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/patologia , Transtornos Parkinsonianos/diagnóstico , Transtornos Parkinsonianos/diagnóstico por imagem , Cintilografia , Estatística como Assunto , Paralisia Supranuclear Progressiva/patologia
15.
J Eur Acad Dermatol Venereol ; 24(4): 403-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19778361

RESUMO

BACKGROUND AND OBJECTIVES: Patients report well-being as they are treated with phototherapy. We investigated hormone parameters and psychological well-being after phototherapy in a placebo-controlled study. METHODS: A total of 77 patients with dermatological conditions and 22 healthy volunteers were divided into four groups. The patients received phototherapy either on the whole body or only on hands and/or feet. The volunteers were given either whole-body phototherapy or placebo light. Serum or plasma samples were analysed for cortisol, calcium, magnesium, phosphate, TSH, T(4), T(3) and 25-hydroxyvitamin D, and urine samples for cortisol. Patients and volunteers answered a questionnaire before and 6 weeks after phototherapy/placebo light. Psychiatric ratings were performed according to the Comprehensive Psychopathological Self-rating Scale for Affective Syndromes, a self-report version of which has been transformed to correspond to the Montgomery-Asberg Depression Rating Scale (MADRS). RESULTS: In the patients who received whole-body irradiation, we observed a significant improvement in both MADRS score and cognitive-symptom score after the completion of phototherapy. We also observed a significantly higher level of 25-hydroxyvitamin D after phototherapy, but no difference in the other hormone parameters. CONCLUSION: Whole-body phototherapy of patients with dermatological conditions results in improved well-being and significantly higher levels of 25-hydroxyvitamin D in serum.


Assuntos
Hormônios/sangue , Dermatopatias/psicologia , Dermatopatias/radioterapia , Terapia Ultravioleta/métodos , Terapia Ultravioleta/psicologia , Adulto , Afeto , , Mãos , Humanos , Hidrocortisona/sangue , Pessoa de Meia-Idade , Terapia PUVA/métodos , Terapia PUVA/psicologia , Placebos , Testes Psicológicos , Inquéritos e Questionários , Tiroxina/sangue , Tri-Iodotironina/sangue , Vitamina D/análogos & derivados , Vitamina D/sangue , Irradiação Corporal Total/métodos , Irradiação Corporal Total/psicologia
16.
Eur J Neurol ; 16(12): 1278-84, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19538208

RESUMO

BACKGROUND AND PURPOSE: The study aims to describe the frequency, pattern and determinants of cognitive function in patients with newly diagnosed Parkinson's disease (PD); to compare patients with impaired cognition to patients with intact cognition; and to compare to matched healthy controls. METHODS: Patients were identified in a longitudinal population based study of idiopathic non-drug induced parkinsonism. Eighty-eight newly diagnosed patients with PD and no dementia were included during a four year period. The patients and 30 age- and sex-matched healthy control subjects underwent a comprehensive neuropsychological assessment. RESULTS: Patients performed significantly worse than healthy controls in a majority of neuropsychological tests. Test results in attention, psychomotor function, episodic memory (free recall), executive function and category fluency were significantly lower in the patient group. Comparison with normative data revealed that 30% of the patients had deficits in > or =1 cognitive domain (episodic memory, executive function and verbal function). Seventy per cent of the patients had normal performance. Unified Parkinson's Disease Rating Scale (UPDRS) III sub scores; speech, facial expression, rigidity and bradykinesia were significantly higher, and disease duration shorter amongst the cognitively impaired than amongst the cognitively intact patients. Tremor showed no difference. Education level was an independent predictor of dysfunction in patients with > or =2 cognitive domains affected. CONCLUSION: Cognitive dysfunction is common in untreated patients in early PD, affecting attention, psychomotor function, episodic memory, executive function and category fluency. Education level was an independent predictor of severe cognitive dysfunction.


Assuntos
Transtornos Cognitivos/complicações , Transtornos Cognitivos/epidemiologia , Doença de Parkinson/complicações , Idoso , Feminino , Humanos , Masculino , Testes Neuropsicológicos
17.
Clín. investig. arterioscler. (Ed. impr.) ; 20(5): 190-199, sept. 2008. ilus
Artigo em Es | IBECS | ID: ibc-68336

RESUMO

Introducción. El colesterol es necesario para la proliferación y la correcta progresión del ciclo celular. La inhibición sostenida de la biosíntesis de colesterol inhibe la citocinesis y da lugar a la aparición de células poliploides, efectos que pueden implicar la participación de las vías de estrés. Objetivo. Estudiar el efecto de la inhibición terminal de la biosíntesis de colesterol sobre la vía de p38 MAPK y su papel en la progresión del ciclocelular. Metodología. La inhibición de la biosíntesis de colesterol en las células promielocíticas humanasHL-60 se llevó a cabo con SKF 104976. En determinados casos, junto a este inhibidor, se inhibieron las vías de p38 MAPK y ERK1/2empleando SB 203580 y PD 98059,respectivamente. El ciclo celular se estudió por marcaje con yoduro de propidio e incorporación de bromodesoxiuridina y análisis por citometría de flujo, y la expresión de proteínas se analizó por Western blot. Resultados. La inhibición de la biosíntesis de colesterol produjo la acumulación de células enG2/M y una activación transitoria de p38 MAPK, efectos que fueron revertidos por las lipoproteínas de baja densidad (LDL), demostrando que se debían a la deficiencia de colesterol. En aquellas condiciones, la adición de SB 203580 aceleró la replicación del ADN acompañada de un aumento de la poliploidía. Contrariamente, la adición de PD98059 inhibió la síntesis de ADN. Ni la inhibición de p38 MAPK ni la de ERK impidieron la división de las células previamente tratadas con SKF104976 tras suplementarlas con LDL, ni de las células previamente sincronizadas en prometafase con nocodazol. Conclusiones. La inhibición de la biosíntesis de colesterol activa la vía de p38 MAPK a fin de impedir la poliploidía pero no tiene efecto sobre la culminación de la mitosis (AU)


Introduction. Cells require cholesterol for proliferation and correct progression of the cell cycle. In the absence of cholesterol, the cells fail tounder go cytokines is and polynucleated cells are generated. These effects could be mediated by stress signal transduction pathways. Objective. To study the effects of cholesterol biosynthesis inhibition on the activity of p38MAPK and to evaluate the role of this pathway on cell cycle progression. Methodology. Human leukemia cells (HL-60)were incubated in the presence of SKF 104976, an inhibitor of cholesterol biosynthesis. In some cases inhibitors of p38 MAPK and ERK1/2, namely SB203580 and PD 98059, were added to the medium. Cell cycle progression was studied by flow citometry, both DNA content and bromodeoxyuridine incorporation into DNA, and protein expression of p38 MAPK was analyzed by western blot. Results. Inhibition of cholesterol biosynthesis led to accumulation of cells in G2/M and a transient activation of p38 MAPK. These effects were reversed by supplementing the medium with LDL. The addition of SB 203580 accelerated DNA replication, which was accompanied by an increase of polyploidy. By contrast, the addition of PD98059 inhibited DNA synthesis. Lastly, neither the inhibition of p38 MAPK nor ERK affected the division of cells treated with the cholesterol biosynthesis inhibitor following LDL provision, or mitosis completion from metaphase of cells previously synchronized with nocodazole. Conclusions. Cholesterol deficiency induces p38MAPK pathway activation in order to prevent polyploidy, but has no effect on mitosis completion (AU)


Assuntos
Anticolesterolemiantes , Colesterol/análise , Proteínas Adaptadoras de Transporte Vesicular/análise , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ativação Enzimática , Divisão Celular/fisiologia , Colesterol/deficiência , Inibidores Enzimáticos/farmacologia , Células HL-60/enzimologia , Células HL-60/metabolismo , Eletroforese/métodos , Western Blotting/métodos
18.
Phys Rev Lett ; 99(14): 147001, 2007 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-17930704

RESUMO

We investigate quantum transport in a normal-superconductor graphene heterostructure, including the possibility of an anisotropic pairing potential in the superconducting region. We find that under certain circumstances, the conductance displays an undamped, oscillatory behavior as a function of applied bias voltage. Also, we investigate how the conductance spectra are affected by a d-wave pairing symmetry. These results combine unusual features of the electronic structure of graphene with the unconventional pairing symmetry found for instance in high-Tc superconductors.

20.
Phys Rev Lett ; 97(14): 147002, 2006 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-17155285

RESUMO

We study tunneling currents in a model consisting of two nonunitary ferromagnetic spin-triplet superconductors separated by a thin insulating layer. We find a novel interplay between ferromagnetism and superconductivity, manifested in the Josephson effect. This offers the possibility of tuning dissipationless currents of charge and spin in a well-defined manner by adjusting the magnetization direction on either side of the junction.

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