RESUMEN
Fully absorption coefficient corrected Raman spectra were obtained in La2-xSrxCuO4. The B1g spectra have a Fleury-Loudon type two-magnon peak (resonant term) whose energy decreases from 3180 cm(-1) (394 meV) to 440 cm(-1) (55 meV) on increasing the carrier density from x = 0 to 0.25, while the B2g spectra have a 1000-3500 cm(-1) (124-434 meV) hump (hill) whose lower-edge energy increases from x = 0 to 0.115 and then stays constant to x = 0.25. The B2g hump is assigned to the electronic scattering (non-resonant term) of the spectral function with magnetic self-energy. The completely different carrier density dependence arises from anisotropic magnetic excitations of spin-charge stripes. The B1g spectra were assigned to the sum of k ⥠and k⥠stripe excitations and the B2g spectra to k⥠stripe excitations according to the calculation by Seibold and Lorenzana (2006 Phys. Rev. B 73 144515). The k ⥠and k⥠stripe excitations in fluctuating spin-charge stripes were separately detected for the first time. The appearance of only k⥠stripe excitations in the electronic scattering arises from the charge hopping perpendicular to the stripe. This is the same direction as the Burgers vector of the edge dislocation in metal. The successive charge hopping in the Burgers vector direction across the charge stripes may cause Cooper pairs as predicted by Zaanen et al (2004 Ann. Phys. 310 181). Indeed, this is supported by the experimental fact that the superconducting coherent length coincides with the inter-charge stripe distance in the wide carrier density range. The one-directional charge hopping perpendicular to the stripe causes the flat Fermi surface and the pseudogap near (π,0) and (0,π), but the states around (π/2,π/2) cannot be produced. The low-energy Raman scattering disclosed that the electronic states at the Fermi arc around (π/2,π/2) are coupled to the A1g soft phonon of the tetragonal-orthorhombic phase transition. This suggests that the Fermi arc is produced by the electron-phonon interaction. All the present Raman data suggest that Cooper pairs are formed at moving edge dislocations of dynamical charge stripes.
RESUMEN
In a strongly correlated electron system, the single-particle spectral function changes into a coherent peak and incoherent humps which extend over 1 eV. The incoherent parts lose the symmetry and k dependence, so that the Raman spectra with different symmetries become identical and they are expressed by the optical conductivity. We found that the B1g and B2g spectra in La(2-x)Sr(x)CuO4 become identical above 2000 cm(-1) in the underdoped phase, if Fleury-Loudon type B1g two-magnon scattering is removed. The first Raman susceptibility moment correlates with the generalized optical conductivity moment. The good correlation arises from the incoherent states of a hump from 1000 to 4000 cm(-1). The hump is the only structure of the incoherent electronic states in the mid-infrared absorption spectra below 1.4 eV at low carrier densities. The energy is twice the separated dispersion segments of the spin wave in the k(perpendicular) stripe direction. The incoherent state is formed by the magnetic excitations created by the hole hopping in the antiferromagnetic spin stripes in the real space picture.
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Lantano/química , Espectrometría Raman/métodos , Ensayo de Materiales , Refractometría , Estadística como AsuntoRESUMEN
OBJECTIVE: We propose new classification criteria for Sjögren's syndrome (SS), which are needed considering the emergence of biologic agents as potential treatments and their associated comorbidity. These criteria target individuals with signs/symptoms suggestive of SS. METHODS: Criteria are based on expert opinion elicited using the nominal group technique and analyses of data from the Sjögren's International Collaborative Clinical Alliance. Preliminary criteria validation included comparisons with classifications based on the AmericanEuropean Consensus Group (AECG) criteria, a model-based "gold standard"obtained from latent class analysis (LCA) of data from a range of diagnostic tests, and a comparison with cases and controls collected from sources external to the population used for criteria development. RESULTS: Validation results indicate high levels of sensitivity and specificity for the criteria. Case definition requires at least 2 of the following 3: 1) positive serum anti-SSA and/or anti-SSB or (positive rheumatoid factor and antinuclear antibody titer >1:320), 2) ocular staining score >3, or 3) presence of focal lymphocytic sialadenitis with a focus score >1 focus/4 mm2 in labial salivary gland biopsy samples. Observed agreement with the AECG criteria is high when these are applied using all objective tests. However, AECG classification based on allowable substitutions of symptoms for objective tests results in poor agreement with the proposed and LCA-derived classifications. CONCLUSION: These classification criteria developed from registry data collected using standardized measures are based on objective tests. Validation indicates improved classification performance relative to existing alternatives, making them more suitable for application in situations where misclassification may present health risks.
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Fenotipo , Síndrome de Sjögren/clasificación , Síndrome de Sjögren/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antinucleares/sangre , Biopsia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Factor Reumatoide/sangre , Glándulas Salivales/patología , Sensibilidad y Especificidad , Sialadenitis/patología , Sociedades Médicas , Estados UnidosRESUMEN
BACKGROUND: Mikulicz's disease (MD) has been considered as one manifestation of Sjögren's syndrome (SS). Recently, it has also been considered as an IgG(4)-related disorder. OBJECTIVE: To determine the differences between IgG(4)-related disorders including MD and SS. METHODS: A study was undertaken to investigate patients with MD and IgG(4)-related disorders registered in Japan and to set up provisional criteria for the new clinical entity IgG(4)-positive multiorgan lymphoproliferative syndrome (IgG(4)+MOLPS). The preliminary diagnostic criteria include raised serum levels of IgG(4) (>135 mg/dl) and infiltration of IgG(4)(+) plasma cells in the tissue (IgG(4)+/IgG+ plasma cells >50%) with fibrosis or sclerosis. The clinical features, laboratory data and pathologies of 64 patients with IgG(4)+MOLPS and 31 patients with typical SS were compared. RESULTS: The incidence of xerostomia, xerophthalmia and arthralgia, rheumatoid factor and antinuclear, antiSS-A/Ro and antiSS-B/La antibodies was significantly lower in patients with IgG(4)+MOLPS than in those with typical SS. Allergic rhinitis and autoimmune pancreatitis were significantly more frequent and total IgG, IgG(2), IgG(4) and IgE levels were significantly increased in IgG(4)+MOLPS. Histological specimens from patients with IgG(4)+MOLPS revealed marked IgG(4)+ plasma cell infiltration. Many patients with IgG(4)+MOLPS had lymphocytic follicle formation, but lymphoepithelial lesions were rare. Few IgG(4)+ cells were seen in the tissue of patients with typical SS. Thirty-eight patients with IgG(4)+MOLPS treated with glucocorticoids showed marked clinical improvement. CONCLUSION: Despite similarities in the involved organs, there are considerable clinical and pathological differences between IgG(4)+MOLPS and SS. Based on the clinical features and good response to glucocorticoids, we propose a new clinical entity: IgG(4)+MOLPS.
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Inmunoglobulina G/análisis , Trastornos Linfoproliferativos/inmunología , Enfermedad de Mikulicz/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Diagnóstico Diferencial , Femenino , Glucocorticoides/uso terapéutico , Humanos , Aparato Lagrimal/patología , Trastornos Linfoproliferativos/diagnóstico , Trastornos Linfoproliferativos/tratamiento farmacológico , Trastornos Linfoproliferativos/patología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedad de Mikulicz/diagnóstico , Enfermedad de Mikulicz/tratamiento farmacológico , Enfermedad de Mikulicz/patología , Prednisolona/uso terapéutico , Estudios Retrospectivos , Glándulas Salivales Menores/patología , Síndrome de Sjögren/diagnóstico , Síndrome de Sjögren/inmunología , Síndrome de Sjögren/patología , Síndrome , Adulto JovenRESUMEN
We use ultrashort intense laser pulses to study superconducting state vaporization dynamics in La2-xSrxCuO4 (x=0.1 and 0.15) on the femtosecond time scale. We find that the energy density required to vaporize the superconducting state is 2.0+/-0.8 and 2.6+/-1.0 K/Cu for x=0.1 and 0.15, respectively. This is significantly greater than the condensation energy density, indicating that the quasiparticles share a large amount of energy with the boson glue bath on this time scale. Considering in detail both spin and lattice energy relaxation pathways which take place on the relevant time scale of approximately 10(-12) s, the experiments appear to favor phonon-mediated pair-breaking mechanisms over spin-mediated pair breaking.
RESUMEN
Optical reflectivity measurements were performed on a single crystal of the d-electron heavy-fermion (HF) metal LiV2O4. Our results evidence the highly incoherent charge dynamics above T* approximately 20 K and the redistribution of the spectral weight of the optical conductivity over broad energy scales ( approximately 5 eV) as the quantum coherence of the charge carriers is recovered. This reveals that LiV2O4 is close to a correlation-driven insulating state and indicates that, in sharp contrast to f-electron HF Kondo-lattice systems, strong electronic correlation effects dominate the heavy quasiparticle formation in LiV2O4.
RESUMEN
The aim of this study was to clarify the nature of the clonal lymphocyte infiltration in Sjögren's syndrome (SS) patients associated with lymphoproliferative disorders. We examined B cell clonality in lymphoproliferative tissues from six primary SS patients associated with lymphoproliferative disorders or lymphoma by cloning and sequencing of the gene rearrangement of the immunoglobulin heavy chain complementarity determining region 3 (IgVH-CDR3). Three patients with sequential observation showed progressional clonal expansion with the presence of the same subclone in different tissues during the course of disease. Among them, one patient developed mucosa-associated lymphoid tissue (MALT) lymphoma in glandular parotid. The other three SS patients concomitant with malignant B cells lymphomas showed different clonal expansion of B cells between nodal sites and salivary glands. The cloanality analysis indicated that monoclonal B cell population could spread from one glandular site to another site during the course of SS, suggesting that the malignant clone may arise from the general abnormal microenvironment, not restricted to the glandular tissue, in some SS patients.
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Linfocitos B/patología , Trastornos Linfoproliferativos/patología , Células Madre Neoplásicas/patología , Síndrome de Sjögren/patología , Anciano , Anciano de 80 o más Años , Secuencia de Aminoácidos , Regiones Determinantes de Complementariedad/genética , Progresión de la Enfermedad , Femenino , Reordenamiento Génico de Cadena Pesada de Linfocito B , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Linfoma de Células B/patología , Linfoma de Células B de la Zona Marginal/patología , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa/métodosRESUMEN
The present systematic Raman scattering experiments reveal the phason and amplitudon of the charge density wave (CDW) mode in the charge stripes of La(2-x)Sr(x)CuO4. Only about 15% of the electronic density of states condenses into the CDW state. The symmetries of the CDW modes change by the rotation of the stripes at the insulator-metal transition. The energy of the phason is finite at 0.06 < or = x < or = 0.1 and zero at x = 0.035 and 0.115 < or = x < or = 0.135, which suggests that the CDW is commensurate at 0.06 < or = x < or = 0.1 and incommensurate otherwise. The zero-energy phason seems to reduce T(c) at x = 1/8.
RESUMEN
Optical conductivity measurements on the organic metal theta-(BEDT-TTF)2I3 revealed that the system crosses over rapidly from a coherent quasiparticle state to an incoherent state with temperature. Despite the metallic temperature dependence of resistivity, a well-defined Drude peak at low temperatures turns into a far-infrared peak with temperature. The peak energy shifts to higher frequencies and, simultaneously, the spectral weight is transferred to high frequencies beyond the electron band width. These characteristics imply that theta-(BEDT-TTF)2I3, so far believed to be a typical metal, is in fact a strongly correlated electron system with "bad-metal" character.
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Compuestos Organometálicos/química , Análisis Espectral/métodos , Compuestos de Sulfhidrilo/química , Conductividad Eléctrica , Óptica y Fotónica , Protones , TermodinámicaRESUMEN
The objective of this study was to detect autoantibodies against granzyme B cleavage products in sera from patients with primary Sjögren's syndrome (SS). Cell lysates derived from human salivary gland (HSG) cell lines were incubated with granzyme B. The susceptibility to the generation of cleavage fragments of SS autoantigens was assayed by immunoblotting using sera from 57 primary SS patients, 17 primary SS patients with malignant lymphoma (ML), 28 systemic lupus erythematosus (SLE) patients, and 20 healthy controls. A 27 kD protein was recognized by serum autoantibodies in 8 (14.0%) of 57 primary SS patients, 5 (29.4%) of 17 SS patients with ML, 2 (7.1%) of 28 SLE patients, but not in 20 normal subjects. This protein was recognized by anti-SSB (La) monoclonal antibodies. Granzyme B-treated recombinant La protein was also shown to migrate as a discrete 27 kD protein by SDS PAGE. Blocking studies demonstrated the existence of an apoptosis-specific B cell epitope present in sera from 2 of 8 primary SS patients and in 2 of 5 primary SS patients with ML which recognized the 27 kD protein. Granzyme B-induced La fragments are generated during cytotoxicity in vitro. This is the first report describing autoantibodies in sera from primary SS patients that specifically recognize fragments of the La protein that are produced by the granzyme B protease.
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Apoptosis/inmunología , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Ribonucleoproteínas/inmunología , Serina Endopeptidasas/inmunología , Síndrome de Sjögren/inmunología , Adulto , Anciano , Autoanticuerpos/sangre , Linfocitos B/inmunología , Línea Celular , Sistema Libre de Células/inmunología , Citotoxicidad Inmunológica/inmunología , Femenino , Granzimas , Humanos , Lupus Eritematoso Sistémico/inmunología , Linfoma/inmunología , Masculino , Persona de Mediana Edad , Antígeno SS-BRESUMEN
The magnetic state in LaCoO3 changes from the low spin state (S=0) to the mixed state with a thermally excited intermediate spin state (IS) (S=1) above about 50 K. The partially filled e(g) orbital in the IS state has a nature of Jahn-Teller (JT) distortion. The cooperative JT distortion causes an orbital order. We found that all Raman active phonon modes are affected by the excitation of IS Co3+ ions. Especially, the JT vibration mode shows anomalous temperature dependence.
RESUMEN
A 43-yr-old Japanese woman presented with mild anemia, leukocytosis and splenomegaly in May 1984. Splenomegaly and anemia gradually progressed. Sixteen years later, in October 2000, she developed inguinal lymphadenopathy. Biopsy of the lymph node revealed infiltration of blasts, megakaryocytes, fibroblasts and myeloid cells. Large blasts with basophilic cytoplasm with cytoplasmic projections appeared in the peripheral blood. These blasts were negative in peroxidase stain, positive in acid phosphatase and weakly positive in periodic acid-Schiff stain. Immunohistochemical staining with monoclonal antibodies revealed that these blasts were positive with anti-CD41 (glycoprotein IIb/IIIa) and negative with other monoclonal antibodies. So diagnosis of granulocytic sarcoma in megakaryoblastic transformation from chronic idiopathic myelofibrosis was made. A cytogenetic study revealed that bone marrow cells were 46,XX del(13)(q?) initially and additional abnormalities including der(5,5,11)(q11;q13)ins(5;?)(q11;?) were found when she developed megakaryoblastic transformation. Granulocytic sarcoma of megakaryoblastic transformation from chronic idiopathic myelofibrosis is a rare event. Immunophenotyping with monoclonal antibody for CD41(glycoprotein IIb/IIIa) confirmed the diagnosis.
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Leucemia Megacarioblástica Aguda/etiología , Mielofibrosis Primaria/complicaciones , Sarcoma Mieloide/etiología , Diferenciación Celular , Transformación Celular Neoplásica , Enfermedad Crónica , Femenino , Humanos , Leucemia Megacarioblástica Aguda/patología , Ganglios Linfáticos/patología , Megacariocitos/patología , Persona de Mediana Edad , Mielofibrosis Primaria/patología , Sarcoma Mieloide/patologíaRESUMEN
OBJECTIVE: To determine whether the clinical and laboratory characteristics of anticentromere antibody (ACA) positive, anti-SSA/Ro antibody (SSA) negative primary Sjogren's syndrome (SS) differ from SSA positive, ACA negative primary SS. METHODS: Twelve patients with ACA positive primary SS (ACA SS) and 19 patients with SSA positive primary SS (SSA SS) were examined. We compared the age, laboratory data, proportion with Raynaud's phenomenon (RP), activity of natural killer cells (NK), titer of antibodies against Epstein-Barr virus, and histological findings of minor labial salivary glands. The presence of anti-chromo antibodies (AChA) was evaluated by immunoblotting of patients' sera. RESULTS: The mean age of the ACA SS group was higher than that of the SSA SS group (p < 0.05). Serum IgG level was lower in ACA SS than in SSA SS (p < 0.0001). Serum IgG level of the ACA SS group with one exception was close to the normal range. Leukocytopenia was less frequently observed in ACA SS than in SSA SS (p < 0.05). RP was seen more frequently in the ACA SS group than the SSA SS group (p < 0.05). NK activity of the ACA SS group was higher than that of the SSA SS group (p < 0.05). Most of the ACA SS patients' NK activity was normal, in contrast to the tendency for NK activity in SS to be low. Virus capsid antigen IgA titer of the ACA SS group was lower than that of the SSA SS group (p < 0.05). Histological findings of minor labial salivary glands of both groups showed a similar severity of lymphocytic infiltrates, destruction of normal structures, and pattern of infiltrating lymphocyte subsets. AChA was positive in 11 of the 12 sera of ACA SS patients. CONCLUSION: The results confirm that ACA positive primary SS differs from SSA positive classic SS in several significant respects.
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Autoanticuerpos/sangre , Centrómero/inmunología , Síndrome de Sjögren/inmunología , Anciano , Anciano de 80 o más Años , Antígenos Virales/inmunología , Autoantígenos/inmunología , Femenino , Herpesvirus Humano 4/inmunología , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Linfocitos/inmunología , Persona de Mediana Edad , Ribonucleoproteínas/inmunología , Glándulas Salivales Menores/inmunología , Glándulas Salivales Menores/patología , Síndrome de Sjögren/patología , Antígeno SS-BRESUMEN
The urea-induced unfolding transition of equine beta-lactoglobulin was studied at pH 8.7 using circular dichroism (CD), ultracentrifugation, and gel filtration chromatography. The unfolding transition curves showed that at least one intermediate accumulates at moderate concentrations of urea. Furthermore, analytical ultracentrifugation experiments indicated that the intermediate forms a dimer. Thus, the urea-induced unfolding transition was measured by CD at various protein concentrations and was analyzed by a model assuming the four conformational states (the native, intermediate, dimeric intermediate, and unfolded states). The characteristics of the intermediate are markedly different from those of the intermediate previously observed at pH 4.0 or 1.5. The intermediate at pH 8.7 does not show the intense far-ultraviolet CD suggestive of the nonnative alpha-helix.
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Lactoglobulinas/química , Lactoglobulinas/efectos de los fármacos , Urea/farmacología , Animales , Bovinos , Dicroismo Circular , Dimerización , Caballos , Concentración de Iones de Hidrógeno , Desnaturalización Proteica/efectos de los fármacos , Pliegue de Proteína , Espectrometría de Fluorescencia/métodosRESUMEN
To explore the relationships between polyol pathway-related enzymes and pathologic features, we examined the immunohistochemical expression of aldose reductase (AR) and sorbitol dehydrogenase (SDH) in the peripheral nerve and kidney tissues collected postmortem from diabetic patients and compared it with those from non-diabetic patients. Tissue AR protein concentrations were also quantified. In non-diabetic patients, AR distributed in pericytes, smooth muscle cells of endo- and epi-neurial microvessels, Schwann cells in the sciatic nerve, and tubular cells of the renal medulla. By contrast, positive SDH reactions were observed in tubular cells of the renal cortex but were faint in the sciatic nerve. Diabetic patients frequently showed dense AR expressions in the sciatic nerve. In nephropathic diabetic patients, the glomerular mesangial area showed diffuse positive reactions for AR. The severity of structural changes in glomeruli correlated with the intensity of immunoreactive AR (r2=0.626, P<0.01). AR contents in the renal cortex and sciatic nerve from diabetic patients were 1.5- and 1.8-fold greater than those from non-diabetic patients, respectively (P<0.05 for both). These findings are the first to demonstrate enhanced AR expressions in peripheral nerve and renal glomeruli in diabetic patients and its relevance to the characteristic pathology.
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Aldehído Reductasa/metabolismo , Nefropatías Diabéticas/enzimología , Glomérulos Renales/enzimología , Nervios Periféricos/enzimología , Adulto , Anciano , Nefropatías Diabéticas/patología , Femenino , Humanos , Inmunohistoquímica , Glomérulos Renales/patología , L-Iditol 2-Deshidrogenasa/metabolismo , Masculino , Persona de Mediana Edad , Nervios Periféricos/patologíaRESUMEN
Cyclosporin A (CsA) is used to prevent rejection in transplantation and to treat autoimmune and hematologic diseases such as aplastic anemia. However, the tumor growth-promoting effect of CsA remains controversial. We report the case of a 24-year-old man who developed acute lymphoblastic leukemia of precursor-T-cell origin after 75 months of treatment with CsA for aplastic anemia. The surface antigen phenotype of his leukemic cells was CD2+, CD3+, CD5+, CD7+, CD4-, CD8-, CD10-, CD20-, CD34-, CD41-, and CD56-. Southern blot analysis revealed a monoclonal rearrangement of T-cell receptor-Jgamma nongermline fragments in HindIII digestion.
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Anemia Aplásica/tratamiento farmacológico , Ciclosporina/efectos adversos , Leucemia de Células T/inducido químicamente , Leucemia-Linfoma Linfoblástico de Células Precursoras/inducido químicamente , Adolescente , Anemia Aplásica/complicaciones , Transformación Celular Neoplásica/efectos de los fármacos , Células Clonales , Ciclosporina/administración & dosificación , Reordenamiento Génico , Humanos , Inmunofenotipificación , Leucemia de Células T/patología , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Receptores de Antígenos de Linfocitos T/genéticaRESUMEN
We report a case of 55 year-old woman with six year history of Sjögren's syndrome developed fatal rapidly progressive interstitial pneumonia. She had been well until February 1999. She developed swelling and erythematous lesions in the cheek and hands in spring 1999. She was admitted to our hospital for investigations of skin lesions in May 1999. Physical examination on admission revealed small hemorrhagic lesions in the nailfold. Serum CK level was slightly elevated. Electromyogram and MRI suggested mild myositis in the proximal upper extremities. She was suspected to have dermatomyositis along with Sjögren's syndrome. Prednisolone 10 mg/day had been given for her skin problems since March 1999. Suddenly, dyspnea on exertion was appeared on 34th day of admission. Chest X-ray film showed an acute worsening of interstitial pneumonia. Methylprednisolone pulse therapy (1000 mg for 3 days) and cyclophosphamide pulse therapy (500 mg for a day) were started, and she was subsequently treated with 60 mg/day of prednisolone and 250 mg/day of Cyclosporin A. However, interstitial pneumonia did not respond to the treatment, and pneumomediastinum and pneumothorax have developed. She died of respiratory failure on 55th day. We consider that most likely explanation for fatal interstitial pneumonia is concomitantly occurred dermatomyositis.
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Dermatomiositis/etiología , Enfermedades Pulmonares Intersticiales/etiología , Síndrome de Sjögren/complicaciones , Ciclofosfamida/administración & dosificación , Ciclosporina/administración & dosificación , Progresión de la Enfermedad , Resultado Fatal , Femenino , Humanos , Metilprednisolona/administración & dosificación , Persona de Mediana Edad , Prednisolona/administración & dosificación , Quimioterapia por Pulso , Síndrome de Sjögren/tratamiento farmacológicoRESUMEN
PURPOSE: The purpose of this work was to compare the diagnostic accuracy of MR sialography with that of salivary gland scintigraphy in Sjögren syndrome. METHOD: One hundred thirty patients clinically suspected of having Sjögren syndrome were examined by MR sialography and salivary gland scintigraphy. A labial gland biopsy was performed in all patients. Imaging findings of MR sialography and salivary gland scintigraphy were compared with the results of labial gland biopsy. RESULTS: From the results of labial gland biopsy, the diagnosis of Sjögren syndrome was established in 80 patients. Abnormally high T2 signal intensity areas on MR sialography and decreased uptake and delayed excretion of [(99m)Tc]pertechnetate on salivary gland scintigraphy were well seen in patients with Sjögren syndrome. For the diagnosis of Sjögren syndrome, salivary gland scintigraphy showed higher sensitivity than MR sialography. On the other hand, MR sialography showed higher specificity and positive predictive value (PPV) than salivary gland scintigraphy. Overall diagnostic accuracy was 83% for MR sialography and 72% for salivary gland scintigraphy. CONCLUSION: The high PPV of MR sialography suggests that MR sialography is the preferred imaging modality in patients suspected of having Sjögren syndrome.