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1.
J Visc Surg ; 159(2): 121-135, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35249857

RESUMO

The spleen can be affected by many conditions, some of which are easily diagnosed by conventional imaging, mainly using computed tomography scans and magnetic resonance imaging. Despite the contribution of functional radiology techniques such as positron emission tomography, it is sometimes difficult to diagnose certain focal splenic lesions and definitive diagnosis sometimes requires histological confirmation by percutaneous biopsy or more rarely by diagnostic intervention. Once a diagnosis has been established, treatment is based mainly on surgery: total splenectomy for malignant lesions, or partial splenectomy whenever possible for benign lesions benign that are symptomatic and/or at risk of rupture.


Assuntos
Esplenopatias , Neoplasias Esplênicas , Humanos , Imageamento por Ressonância Magnética/métodos , Esplenectomia/métodos , Esplenopatias/diagnóstico por imagem , Esplenopatias/cirurgia , Neoplasias Esplênicas/diagnóstico por imagem , Neoplasias Esplênicas/cirurgia , Tomografia Computadorizada por Raios X/métodos
4.
Diagn Interv Imaging ; 101(9): 565-575, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32146131

RESUMO

PURPOSE: To report the computed tomography (CT) features of pancreatic acinar cell carcinoma (ACC) and identify CT features that may help discriminate between pancreatic ACC and pancreatic ductal adenocarcinoma (PDA). MATERIALS AND METHODS: The CT examinations of 20 patients (13 men, 7 women; mean age, 66.5±10.7 [SD] years; range: 51-88 years) with 20 histopathologically proven pancreatic ACC were reviewed. CT images were analyzed qualitatively and quantitatively and compared to those obtained in 20 patients with PDA. Comparisons were performed using univariate analysis with a conditional logistic regression model. RESULTS: Pancreatic ACC presented as an enhancing (20/20; 100%), oval (15/20; 75%), well-delineated (14/20; 70%) and purely solid (13/20; 65%) pancreatic mass with a mean diameter of 52.6±28.0 (SD) mm (range: 24-120mm) in association with visible lymph nodes (14/20; 70%). At univariate analysis, well-defined margins (Odds ratio [OR], 7.00; P=0.005), nondilated bile ducts (OR, 9.00; P=0.007), visible lymph nodes (OR, 4.33; P=0.028) and adjacent organ involvement (OR, 5.67; P=0.02) were the most discriminating CT features to differentiate pancreatic ACC from PDA. When present, lymph nodes were larger in patients with pancreatic ACC (14±4.8 [SD]; range: 7-25mm) than in those with PDA (8.8±4.1 [SD]; range: 5-15mm) (P=0.039). CONCLUSION: On CT, pancreatic ACC presents as an enhancing, predominantly oval and purely solid pancreatic mass that most frequently present with no bile duct dilatation, no visible lymph nodes, no adjacent organ involvement and larger visible lymph nodes compared to PDA.


Assuntos
Carcinoma de Células Acinares , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Idoso , Carcinoma de Células Acinares/diagnóstico por imagem , Carcinoma Ductal Pancreático/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pâncreas/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Tomografia Computadorizada por Raios X
6.
Eur J Radiol ; 119: 108650, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31525680

RESUMO

PURPOSE: To evaluate a strategy that used thermal-ablation of vertebral metastases (VM) to prevent vertebral related events (VRE) in patients with differentiated thyroid cancer (DTC). METHODS: This single center study retrospectively reviewed records and post-operative imaging of all DTC patients treated with thermal-ablation for asymptomatic VMs. Rate of local tumor control at first post-operative imaging, 12 and 24 months after thermal-ablation and rate of VREs at 12 and 24 months among the treated VMs were reported. New VMs that occurred during the follow-up and were not considered for additional thermal-ablation were moniroted and VREs were reported. RESULTS: Thermal-ablation was used to achieve local control of 41 VMs in 28 patients. Median post-treatment follow-up was 22 months [range: 12-80] and the mean delay for first post-operative imaging was 2 months [range: 0.6-7.5]. Local control at first post-operative imaging, 12 and 24 months was achieved in 87.8%, 82.9% and 75.6%, respectively. Among the treated VMs the rates of VRE was 7.3% at 2 years, significantly lower if local control was achieved at first post-operative imaging than if it was not (0% vs 30%, p = 0.011, OR = 0.184 [95%CI = 0.094-0.360]). After thermal-ablation procedures, 19 news VMs occurred in 11 patients (39.2%) with a median interval of 8 months [range 1-26] and remained untreated. Among these untreated VMs, the rate of VREs at 2 years was significantly higher compared to the treated VMs: (36.8% vs. 7.3%, p = 0.008, OR = 0.135, [95%CI = 0.030-0.607]). CONCLUSION: local tumor control of VMs using thermal-ablation decreases the risk of VREs in DTC patients.


Assuntos
Técnicas de Ablação/métodos , Hipertermia Induzida/métodos , Neoplasias da Coluna Vertebral/cirurgia , Neoplasias da Glândula Tireoide/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Vértebras Cervicais/cirurgia , Feminino , Humanos , Vértebras Lombares/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sacro/cirurgia , Neoplasias da Coluna Vertebral/prevenção & controle , Neoplasias da Coluna Vertebral/secundário , Cirurgia Assistida por Computador/métodos , Vértebras Torácicas/cirurgia , Resultado do Tratamento
7.
Diagn Interv Imaging ; 100(11): 679-687, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31331832

RESUMO

PURPOSE: The purpose of this study was to determine the efficacy of salvage cryotherapy for intra-prostatic and local extraprostatic recurrences after curative treatment of prostate adenocarcinoma. MATERIAL AND METHOD: Twenty-eight men (mean age, 69±6 [SD] years; range: 51-82 years) treated with cryoablation for prostatic (N=21) or extraprostatic (N=7) recurrent prostate cancer after radiotherapy with or without associated prostatectomy were included. Technical success, complication and recurrences were reported. Biological recurrence was defined as an elevation ≥2ng/mL of prostate specific antigen (PSA) serum level after the treatment. RESULTS: The mean follow-up was 18 months. Among the 21 patients with intraprostatic recurrence, 14 had successful cryotherapy with a mean decrease in serum prostate-specific antigen (PSA) levels of -5.7±2.6 (SD) ng/mL (range: -2.1 to -16.9ng/mL). Four patients (19%) had early progression and three patients (14%) had delayed biological recurrence (mean time: 15 months). Among the 7 patients with extraprostatic recurrence, 2/7 (291%) had successful cryotherapy with a decrease in PSA serum level of -2.7±1.6 (SD) ng/mL (range: -0.5--5.5ng/mL) and 4/7 (57%) had early biological recurrence after cryotherapy that required androgen deprivation therapy, whereas 1/7 (4%) was lost to follow-up. No major complications were observed for both intra- and extraprostatic recurrence. CONCLUSION: Salvage cryoablation of locally recurrent prostate cancer after curative treatment is feasible and safe when the half prostate is treated. It could delay initiation of androgen deprivation therapy in these patients.


Assuntos
Adenocarcinoma/cirurgia , Criocirurgia/métodos , Recidiva Local de Neoplasia/cirurgia , Neoplasias da Próstata/cirurgia , Terapia de Salvação/métodos , Adenocarcinoma/sangue , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/radioterapia , Idoso , Idoso de 80 Anos ou mais , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/diagnóstico por imagem , Antígeno Prostático Específico/sangue , Prostatectomia , Neoplasias da Próstata/sangue , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Estudos Retrospectivos
8.
Diagn Interv Imaging ; 100(11): 709-719, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31208938

RESUMO

PURPOSE: The purpose of this study was to compare the diagnostic accuracy and inter-reader agreement of unenhanced computed tomography (CT) to those of contrast-enhanced CT for triage of patients older than 75years admitted to emergency department (ED) with acute abdominal pain (AAP). PATIENTS AND METHODS: Two hundred and eight consecutive patients presenting with AAP to the ED who underwent CT with unenhanced and contrast-enhanced images were retrospectively included. There were 90 men and 118 women with a mean age of 85.4±4.9 (SD) (range: 75-101.4years). Three readers reviewed unenhanced CT images first, and then unenhanced and contrast-enhanced CT images as a single set. Diagnostic accuracy was compared to the standard of reference defined as the final diagnosis obtained after complete clinico-biological and radiological evaluation. Correctness of the working diagnosis proposed by the ED physician was evaluated. Intra- and inter-reader agreements were calculated using the kappa test and interclass correlation. Subgroup analyses were performed for patients requiring only conservative management and for those requiring intervention. RESULTS: Diagnostic accuracy ranged from 64% (95% CI: 62-66%) to 68% (95% CI: 66-70%) for unenhanced CT, and from 68% (95% CI: 66-70%) to 71% (95% CI: 69-73%) for both unenhanced and contrast-enhanced CT. Contrast-enhanced CT did not significantly improve the diagnostic accuracy (P=0.973-0.979). CT corrected the working diagnosis proposed by the ED physician in 59.1% (range: 58.1-60.0%) and 61.2% (range: 57.6-65.5%) of patients before and after contrast injection (P>0.05). Intra-observer agreement was moderate to substantial (k=0.513-0.711). Inter-reader agreement was substantial for unenhanced (kappa=0.745-0.789) and combined unenhanced and contrast-enhanced CT (kappa=0.745-0.799). Results were similar in subgroup analyses. CONCLUSION: Unenhanced CT alone is accurate and associated with high degrees of inter-reader agreement for clinical triage of patients older than 75years with AAP in the emergency setting.


Assuntos
Dor Abdominal/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Triagem/métodos , Dor Abdominal/sangue , Dor Abdominal/etiologia , Dor Abdominal/terapia , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Apendicite/diagnóstico por imagem , Colangite/diagnóstico por imagem , Intervalos de Confiança , Meios de Contraste , Diverticulite/diagnóstico por imagem , Serviço Hospitalar de Emergência , Feminino , Humanos , Obstrução Intestinal/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Padrões de Referência , Estudos Retrospectivos , Ruptura Espontânea/diagnóstico por imagem , Úlcera Gástrica/diagnóstico por imagem
9.
Eur Radiol ; 29(4): 2034-2044, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30302591

RESUMO

PURPOSE: To compare the accuracy of MR enterography (MRE) using combined T2-weighted and contrast-enhanced (CE) sequences with that of combined T2- and diffusion-weighted (DW) sequences for the detection of complex enteric Crohn's disease (CD). MATERIALS: Thirty-eight patients who underwent surgery for CD complications and preoperative MRE from 2011 to 2016 were included. MRE examinations were blindly analyzed independently by one junior and one senior abdominal radiologist for the presence of fistula, stenosis and abscesses. During a first reading session, T2-weighted images (WI), steady-state sequences and DW-MRE were reviewed (set 1). During a separate distant session, T2-WI, True-FISP and CE-MRE were reviewed (set 2). Performance of each reader was evaluated by comparison with the standard of reference established using intraoperative and pathological findings. RESULTS: Forty-eight fistulas, 43 stenoses and 11 abscesses were found. For the senior radiologist, sensitivity for the detection of fistula, stenosis and abscess ranged from 80% to 100% for set 1 and 88% to 100% for set 2 and specificity ranged from 56% to 70% for set 1 and 53% to 93% for set 2, with no significant difference between the sets (p = 0.342-0.429). For the junior radiologist, sensitivity ranged from 53% to 63% for set 1 and 64% to 88% for set 2 and specificity ranged from 0% to 25% for set 1 and 17% to 40% for set 2 (p = 0.001 and 0.007, respectively). CONCLUSION: For a senior radiologist, DW-MRE has similar sensitivity as CE-MRE for the detection of CD complications. For a junior radiologist, CE-MRE yields the best results compared with DW-MRE. KEY POINTS: • For experienced readers, DWI has similar diagnostic capability as contrast-enhanced MR imaging for the diagnosis of Crohn's disease complications. • For senior radiologists, gadolinium chelate injection could be waived for the diagnosis of Crohn's disease complications. • The interpretation of DWI for Crohn's disease complications requires some experience.


Assuntos
Meios de Contraste/farmacologia , Doença de Crohn/diagnóstico por imagem , Aumento da Imagem/métodos , Intestino Delgado/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Complicações Pós-Operatórias/diagnóstico , Cuidados Pré-Operatórios/métodos , Adolescente , Adulto , Doença de Crohn/cirurgia , Imagem de Difusão por Ressonância Magnética/métodos , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
10.
Diagn Interv Imaging ; 98(12): 857-863, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28754326

RESUMO

PURPOSE: To compare the respective values of arterial phase, portal venous phase and combination of phases using 64-section multidetector computed tomography (MDCT) for diagnosing acute overt gastrointestinal bleeding (AOGIB). PATIENTS AND METHODS: Forty-nine patients with AOGIB were included. There were 30 men and 19 women, with a mean age of 65.4±15.6 (SD) years [range, 34-91years]. Two observers reviewed MDCT examinations in consensus for presence of active bleeding, location of bleeding site and nature of causative lesion. The different acquisition phases were reviewed independently. RESULTS: AOGIB was identified in 28/49 patients (57%) with the multiphasic set, in 26/49 patients (53%) with arterial phase and in 25/49 patients (51%) with portal venous phase. Multiphasic set helped locate the bleeding site in 40/49 patients (82%). The cause was elucidated in 23/49 patients (47%) with multiphasic set. The differences between set performances were not statistically significant. Sensitivity for depicting AOGIB with the multiphasic set was 92% and specificity was 76%. CONCLUSION: Multiphasic 64-section MDCT has high diagnostic performances in patients with AOGIB. Further studies with a larger population are needed to reach statistical significance and demonstrate better diagnostic performance of multiphasic MDCT in comparison with the arterial or portal phase alone.


Assuntos
Angiografia/métodos , Hemorragia Gastrointestinal/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
Diagn Interv Imaging ; 98(10): 663-675, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28185840

RESUMO

Recent advances in imaging have resulted in marked changes in the investigation of the duodenum, which still remains primarily evaluated with videoendoscopy. However, improvements in computed tomography (CT) and magnetic resonance (MR) imaging have made detection and characterization of duodenal mass-forming abnormalities easier. The goal of this pictorial review was to illustrate the most common conditions of the duodenum that present as mass-forming lesions with a specific emphasis on CT and MR imaging. MR imaging used in conjunction with duodenal distension appears as a second line imaging modality for the characterization of duodenal mass-forming lesions. CT remains the first line imaging modality for the detection and characterization of a wide range of duodenal mass-forming lesions.


Assuntos
Duodenopatias/diagnóstico por imagem , Duodeno/diagnóstico por imagem , Adenocarcinoma/diagnóstico por imagem , Adenoma/diagnóstico por imagem , Malformações Arteriovenosas/diagnóstico por imagem , Glândulas Duodenais/diagnóstico por imagem , Glândulas Duodenais/patologia , Coristoma/diagnóstico por imagem , Divertículo/diagnóstico por imagem , Duodeno/anatomia & histologia , Tumores do Estroma Gastrointestinal/diagnóstico por imagem , Hamartoma/diagnóstico por imagem , Hemangioma/diagnóstico por imagem , Humanos , Hiperplasia/diagnóstico por imagem , Polipose Intestinal/diagnóstico por imagem , Leiomioma/diagnóstico por imagem , Lipoma/diagnóstico por imagem , Linfoma/diagnóstico por imagem , Imageamento por Ressonância Magnética , Tumores Neuroendócrinos/diagnóstico por imagem , Pâncreas , Tomografia Computadorizada por Raios X , Tuberculose Gastrointestinal/diagnóstico por imagem
13.
Diagn Interv Imaging ; 97(12): 1259-1273, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27825642

RESUMO

The increasing use of abdominal imaging has led to a growing incidence of traditionally uncommon pancreatic tumors. These rare tumors have specific imaging features whose knowledge may heighten confidence in characterization and may avoid unnecessary surgical procedures when imaging findings suggest a benign condition. Computed tomography (CT) is the modality with which rare pancreatic tumors are incidentally detected in the majority of cases. Magnetic resonance imaging (MRI) is often performed as a second line examination for further characterization. This review provides an update on CT and MRI findings of rare tumors of the pancreas.


Assuntos
Achados Incidentais , Imageamento por Ressonância Magnética , Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/patologia , Doenças Raras/diagnóstico por imagem , Doenças Raras/patologia , Tomografia Computadorizada por Raios X , Aspiração por Agulha Fina Guiada por Ultrassom Endoscópico , Humanos , Estadiamento de Neoplasias , Pâncreas/diagnóstico por imagem , Pâncreas/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Sensibilidade e Especificidade
14.
Eur J Surg Oncol ; 42(2): 266-72, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26683262

RESUMO

OBJECTIVE: To determine if the presence of cardiophrenic angle lymph nodes (CPALNs) on multidetector-row computed tomography (MDCT) can be considered as an indicator of peritoneal carcinomatosis (PC) in patients with colorectal cancer (CRC). MATERIAL AND METHODS: Two groups of 101 patients each were retrospectively included. Group 1 included patients with PC from CRC and Group 2 included patients with CRC without PC. MDCT examinations were analyzed by two readers working in consensus for the presence or absence of CPALNs and, when present for their dimensions (short and long axis), location (right, left or bilateral) and shape (oval or rounded). RESULTS: Prevalence of CPALNs was 29% in Group 1 and 32% in Group 2. No differences in prevalence of CPALNs were found between the two groups (P = 0.458). Presence of CPALNs had a sensitivity of 29% (95%CI: 23-35%) for the diagnosis of PC and a specificity of 68% (95%CI = 62-74%). No differences in CPALN dimensions, location and shape were found between these two groups. CONCLUSION: Presence of CPALNs cannot be considered as an indicator of PC in patients with CRC. In addition, when present, CPALNs have similar dimensions, location and shapes in patients with PC from CRC than in those without PC.


Assuntos
Carcinoma/diagnóstico , Neoplasias Colorretais/patologia , Linfonodos/diagnóstico por imagem , Neoplasias Peritoneais/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma/secundário , Estudos de Casos e Controles , Diafragma , Feminino , Coração , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores , Neoplasias Peritoneais/secundário , Estudos Retrospectivos , Sensibilidade e Especificidade
15.
Ann Phys Rehabil Med ; 57(9-10): 664-83, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25277540

RESUMO

UNLABELLED: Following severe traumatic brain injury (TBI), failure to adjust language to communication abilities has been described and attributed by many authors to executive function impairment. Interactional dysfunctions may damage family-based, social and vocational equilibrium, and they are of key importance in prognosis of rehabilitation outcome. In conversation, frequently occurring inappropriate formulations connote difficulties in discursive organization and are likely to include numerous digressions, if not confabulations. OBJECTIVE: The main objective of this study was to improve assessment of the non-verbal as well as the verbal aspects of the communication disorders observed in TBI subjects. We have developed and are proposing the grid for linguistic analysis (GALI) of free conversational interchange that constitutes an original French-language tool. We wish to demonstrate its validity as a means of measuring interactive skills in a given population. METHOD: We assessed 17 severely brain injured patients presenting executive dysfunction, who were compared with 34 matched and healthy individuals. Fifty-one 10-minute sequences of free conversation between study participants and therapists were filmed and analyzed by applying the GALI. Three independent raters coded the conversations. Inter-rater reproducibility was considered statistically satisfactory. RESULTS: The results successfully distinguished TBI patients from healthy subjects and thereby underscored the discriminatory value of the tool. A significant correlation was found between the patients' performances in executive tests and in the GALI. CONCLUSIONS: In severe TBI a social handicap results from several associated cognitive disorders. Interactive discourse analysis combining non-verbal with verbal aspects confirms the existence of difficulties in communication that are usually underestimated in classic formal language testing methods. The GALI is likely to meet speech therapists' need for reliable assessment of their patients' interactional difficulties and their consequences in social life.


Assuntos
Lesões Encefálicas/psicologia , Transtornos Cognitivos/etiologia , Transtornos da Comunicação/diagnóstico , Função Executiva , Adolescente , Adulto , Transtornos da Comunicação/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Adulto Jovem
16.
Ann Chir Plast Esthet ; 59(4): 276-9, 2014 Aug.
Artigo em Francês | MEDLINE | ID: mdl-24503521

RESUMO

Primary and metastatic mandibular melanoma are extremely rare. We report the original case of a 55-year-old woman treated 16 years before for a cutaneous melanoma, and now presenting with a huge mandibular amelanotic melanoma. Was it an histologically different mandibular metastasis of the previous cutaneous melanoma, or a metachronous oral amelanotic melanoma?


Assuntos
Neoplasias Mandibulares/secundário , Melanoma Amelanótico/patologia , Melanoma/secundário , Neoplasias Bucais/patologia , Segunda Neoplasia Primária/patologia , Neoplasias Cutâneas/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Boca , Invasividade Neoplásica
17.
Ann Phys Rehabil Med ; 56(1): 51-62, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23369427

RESUMO

Even though new prevention techniques have been developed and are being used during thoraco-abdominal aortic repairs, spinal cord infarction remains a severe and relatively frequent complication of aortic surgery. Infarctions in the territory of the anterior spinal artery are considered the most common. Different clinical pictures related to spinal cord transverse extension wounds are drawn up. In this paper, we present a case report of a subject having presented an isolated motor deficit of the lower limbs and a favorable prognosis, suggesting selective involvement of the anterior horns of the spinal cord subsequent to surgical repair of an aortic dissection. We wish to review the relevant anatomical, clinical and diagnostic characteristics along with current techniques of spinal cord ischemia prevention during and after surgery.


Assuntos
Aorta Torácica/cirurgia , Infarto/etiologia , Paraparesia/etiologia , Complicações Pós-Operatórias , Medula Espinal/irrigação sanguínea , Idoso , Dissecção Aórtica/cirurgia , Aneurisma Aórtico/cirurgia , Humanos , Infarto/diagnóstico , Imageamento por Ressonância Magnética , Masculino , Exame Neurológico , Paraparesia/reabilitação
18.
Phys Chem Chem Phys ; 14(29): 10225-32, 2012 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-22722478

RESUMO

C(α)-C(ß) chromophore bond dissociation in some selected methionine-containing dipeptides induced by UV photons is investigated. In methionine containing dipeptides with tryptophan as the UV chromophore, the tryptophan side chain is ejected either as an ion or as a neutral fragment while in dipeptides with tyrosine, the tyrosine side chain is lost only as a neutral fragment. Mechanisms responsible for these fragmentations are proposed based on measured branching ratios and fragmentation times, and on the results of DFT/B3-LYP calculations. It appears that the C(α)-C(ß) bond cleavage is a non-statistical dissociation for the peptides containing tyrosine, and occurs after internal conversion for those with tryptophan. The proposed mechanisms are governed by the ionization potential of the aromatic side chain compared to that of the rest of the molecule, and by the proton affinity of the aromatic side chain compared to that of the methionine side chain. In tyrosine-containing peptides, the presence of oxygen on sulfur of methionine presumably reduces the ionization potential of the peptide backbone, facilitating the loss of the side chain as a neutral fragment. In tryptophan-containing peptides, the presence of oxygen on methionyl-sulfur expedites the transfer of the proton from the side chain to the sulfoxide, which facilitates the loss of the neutral side chain.


Assuntos
Aminoácidos Aromáticos/química , Carbono/química , Dipeptídeos/química , Metionina/química , Prótons , Sulfóxidos/química , Tirosina/química , Cor , Processos Fotoquímicos , Raios Ultravioleta
19.
J Phys Chem A ; 115(38): 10383-90, 2011 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-21776981

RESUMO

The UV photodissociation dynamics of deprotonated 2'-deoxyadenosine 5'-monophosphate ([5'-dAMP-H](-)) has been studied using a unique technique based on the coincident detection of the ion and the neutral fragments. The observed fragment ions are m/z 79 (PO(3)(-)), 97 (H(2)PO(4)(-)), 134 ([A-H](-)), 177 ([dAMP-H-A-H(2)O](-)), and 195 ([dAMP-H-A](-)), where "A" refers to a neutral adenine molecule. The relative abundances are comparable to that found in previous studies on [5'-dAMP-H](-) employing different excitation processes, i.e., collisions and UV photons. The fragmentation times of the major channels have been measured, and are all found to be on the microsecond time scale. The fragmentation mechanisms for all channels have been characterized using velocity correlation plots of the ion and neutral fragment(s). The findings show that none of the dissociation channels of [5'-dAMP-H](-) is UV specific and all proceed via statistical fragmentation on the ground state after internal conversion, a result similar to fragmentations induced by collisions.


Assuntos
Nucleotídeos de Desoxiadenina/química , Nucleotídeos de Desoxiadenina/efeitos da radiação , Processos Fotoquímicos/efeitos da radiação , Raios Ultravioleta , Conformação de Ácido Nucleico , Prótons
20.
Ann Phys Rehabil Med ; 54(4): 213-24, 2011 Jun.
Artigo em Inglês, Francês | MEDLINE | ID: mdl-21420922

RESUMO

BACKGROUND: Traumatic spinal cord injuries on cervical canal stenosis represent a steadily increasing pathology, of which clinical and functional outcomes remain largely unknown. MATERIAL AND METHODS: We present the results of a prospective study of 20 patients followed for one year who had presented with traumatic spinal cord injury involving initially acute neurological symptoms and cervical canal stenosis defined in the imaging by a Torg ratio<0.8 and a medullary canal ratio>0.65, without vertebral fracture. RESULTS: Traumatic spinal cord injuries on cervical canal stenosis are caused mainly by falls in the elderly population and by unsafe behaviour among younger subjects. Most of the patients present with initially incomplete tetraplegia, and two thirds have centromedullary syndrome. Association of complete tetraplegia with advanced age would seem to be a predictive factor of death in the early post-traumatic period. For incomplete tetraplegics, the main phase of neurological and functional recovery is observed over the first six months. Radiological data and timing of surgery do not appear to affect the prognosis. CONCLUSION: This study underlines the need for individualized specialized care of patients with spinal cord injuries on cervical canal stenosis, particularly according to their demographic and lesional characteristics.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Lesões do Pescoço/complicações , Quadriplegia/etiologia , Traumatismos da Medula Espinal/epidemiologia , Estenose Espinal/complicações , Acidentes por Quedas , Adulto , Idoso , Idoso de 80 Anos ou mais , Síndrome de Brown-Séquard/etiologia , Mergulho/lesões , Feminino , Humanos , Isquemia/etiologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Quadriplegia/reabilitação , Quadriplegia/cirurgia , Radiografia , Recuperação de Função Fisiológica , Índice de Gravidade de Doença , Medula Espinal/irrigação sanguínea , Compressão da Medula Espinal/complicações , Compressão da Medula Espinal/diagnóstico por imagem , Traumatismos da Medula Espinal/diagnóstico por imagem , Traumatismos da Medula Espinal/etiologia , Traumatismos da Medula Espinal/mortalidade , Traumatismos da Medula Espinal/cirurgia , Estenose Espinal/diagnóstico por imagem , Resultado do Tratamento
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