RESUMO
Pathogenic fungi represent a major threat particularly to immunocompromised hosts, leading to severe, and often lethal, systemic opportunistic infections. Although the impaired immune status of the host is clearly the most important factor leading to disease, virulence factors of the fungus also play a role. Factor H (FH) and its splice product FHL-1 represent the major fluid phase inhibitors of the alternative pathway of complement, whereas C4b-binding protein (C4bp) is the main fluid phase inhibitor of the classical and lectin pathways. Both proteins can bind to the surface of various human pathogens conveying resistance to complement destruction and thus contribute to their pathogenic potential. We have recently shown that Candida albicans evades complement by binding both Factor H and C4bp. Here we show that moulds such as Aspergillus spp. bind Factor H, the splicing variant FHL-1 and also C4bp. Immunofluorescence and flow cytometry studies show that the binding of Factor H and C4bp to Aspergillus spp. appears to be even stronger than to Candida spp. and that different, albeit possibly nearby, binding moieties mediate this surface attachment.
Assuntos
Proteína de Ligação ao Complemento C4b/metabolismo , Fator H do Complemento/metabolismo , Proteínas Inativadoras do Complemento/fisiologia , Imunidade , Aspergillus/imunologia , Proteínas Inativadoras do Complemento C3b , Humanos , Ligação ProteicaRESUMO
Jumps of single atoms can be followed on their time and space scale (nanoseconds and Angstroms) by applying nuclear resonance scattering of synchrotron radiation. Here we develop the theory for jump diffusion in two-dimensional systems. Two types of phenomena are noteworthy: apparent acceleration of the nuclear decay and relaxation of hyperfine interactions, in particular, electric quadrupole interactions. The latter effect becomes for the first time one of significance and well measurable due to the inherent anisotropy of the surface. We show how, by way of motional narrowing, to distinguish between the motion of the probe atom itself and the motion of adatoms.
RESUMO
The confinement of materials in low-dimensional structures has significant impact on propagating excitations like phonons. Using the isotope-specific 57Fe nuclear resonant vibrational spectroscopy we were able to determine elastic and thermodynamic properties of ultrathin Fe films on W(110). With decreasing thickness one observes a significant increase of the mean atomic displacement that goes along with an enhancement of vibrational modes at low energies as compared to the bulk. The analysis reveals that these deviations result from atomic vibrations of the single atomic layers at the two boundaries of the film, while the atoms inside the films vibrate almost bulklike.
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AIMS: Comedo carcinoma is generally regarded as the subtype of ductal carcinoma in situ (DCIS) most likely to progress to invasive carcinoma. Increased angiogenesis could be associated with an enhanced risk of progression and might therefore be a marker of poor prognosis, as can be demonstrated for invasive breast tumours. Therefore, the present study investigates the correlations between the expression of oncoproteins (HER2, HER1/EGFR), angiogenic growth factors (VEGF and PD-ECGF/TP) and microvessel density (MVD) in DCIS. METHODS AND RESULTS: Forty-six breast cancer specimens of DCIS were tested immunohistochemically for the expression of angiogenic factors and oncoproteins. Different vascular distribution patterns of DCIS were examined semiquantitatively. Our results showed a significantly inverse correlation between HER1/EGFR and comedo-type DCIS (P = 0.048), but HER1/EGFR expression seemed to be independent of HER2 overexpression. VEGF expression was significantly associated with endoglin expression (P = 0.031) and the cuffing phenomenon (P = 0.017). CONCLUSIONS: The significantly inverse correlation between HER1/EGFR and comedo-type DCIS and the observation that VEGF and the other angiogenic factors tested are independent of HER2 overexpression, suggest that progression of comedo-type DCIS and angiogenesis in breast carcinoma are not regulated via the HER1/EGFR or HER2 pathway.
Assuntos
Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/metabolismo , Carcinoma Intraductal não Infiltrante/irrigação sanguínea , Carcinoma Intraductal não Infiltrante/metabolismo , Neovascularização Patológica , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Carcinoma Intraductal não Infiltrante/enzimologia , Carcinoma Intraductal não Infiltrante/patologia , Distribuição de Qui-Quadrado , Receptores ErbB/metabolismo , Feminino , Genes erbB-1 , Genes erbB-2 , Humanos , Imuno-Histoquímica , Microcirculação/patologia , Pessoa de Meia-Idade , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Estudos Retrospectivos , Timidina Fosforilase/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Neutron spin-echo spectroscopy has been applied to jump diffusion in a crystalline solid. Definite advantages of spin-echo spectroscopy over quasielastic neutron scattering are the direct visual discrimination of fast and slow diffusion processes and the high resolution in the time-energy domain. The potential of the method is demonstrated by way of Ni diffusion in the intermetallic alloy NiGa.
RESUMO
The Mössbauer effect of 57Fe-enriched samples was used to investigate the coupling of 80% sucrose/water, a protein-stabilizing solvent, to vibrational and diffusive modes of the heme iron of CO-myoglobin. For comparison we also determined the Mössbauer spectra of K4 57Fe (CN)6 (potassium ferrocyanide, PFC), where the iron is fully exposed in the same solvent. The temperature dependence of the Mössbauer parameters derived for the two samples proved to be remarkably similar, indicative of a strong coupling of the main heme displacements to the viscoelastic relaxation of the solvent. We show that CO escape out of the heme pocket couples to the same type of fluctuations, whereas intramolecular bond formation involves solvent-decoupled heme deformation modes that are less prominent in the Mössbauer spectrum. With respect to other solvents, however, sucrose shows a reduced viscosity effect on heme displacements and the kinetics of ligand binding due to preferential hydration of the protein. This result confirms thermodynamic predictions of the stabilizing action of sucrose by a dynamic method.
Assuntos
Mioglobina/química , Animais , Fenômenos Biofísicos , Biofísica , Ferrocianetos/química , Heme/química , Cavalos , Técnicas In Vitro , Cinética , Ligantes , Mioglobina/metabolismo , Ligação Proteica , Solventes , Espectroscopia de Mossbauer , Sacarose , Termodinâmica , Viscosidade , ÁguaRESUMO
A 35-year-old man presented with the clinical picture of spontaneous subarachnoid hemorrhage. Four weeks after the first symptoms he noticed blurred vision, and ophthalmological examination detected bitemporal hemianopia. At this time cerebral computed tomography and magnetic resonance imaging showed enlargement of the optic chiasm, and visual evoked potentials revealed delayed latencies. In the cerebrospinal fluid cells and protein content were elevated, and angiotensin-converting enzyme was detectable. Under steroid treatment the patient recovered completely and computed tomography, magnetic resonance imaging, visual evoked potentials, and cerebrospinal fluid findings became normal. Although a great variety of neurological symptoms may occur in neurosarcoidosis, to our knowledge spontaneous subarachnoid hemorrhage as the presenting feature has never been reported before.
Assuntos
Encefalopatias/complicações , Sarcoidose/complicações , Hemorragia Subaracnóidea/etiologia , Adulto , Encefalopatias/líquido cefalorraquidiano , Encefalopatias/diagnóstico por imagem , Tosse , Hemianopsia/etiologia , Humanos , Masculino , Quiasma Óptico/diagnóstico por imagem , Quiasma Óptico/patologia , Radiografia , Sarcoidose/líquido cefalorraquidiano , Sarcoidose/diagnóstico por imagemRESUMO
A CT-controlled method for the treatment of lumbar and cervical disc prolapse is described. Compared with fluoroscopically controlled percutaneous lumbar discectomy, percutaneous treatment of the L5/S1 disc by a dorsal approach is possible even in the presence of high iliac crests, as is described in this paper. In the cervical region the risk of iatrogenic damage is reduced. In a small group of 42 patients, an attempt has been made to remove disc material which is intraforaminal, intraspinal, subligamentous or sequestered. Amongst 79 patients with lumbar and 15 patients with cervical disc prolapse treatment was successful in 85% (after 17 months of observation) and 93% (after 12 months of observation). These figures refer to the early results from a new method. The success of the method will have to be assessed after a larger number of patients has been treated and there has been a longer period of observation.
Assuntos
Vértebras Cervicais/diagnóstico por imagem , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Radiografia Intervencionista , Tomografia Computadorizada por Raios X , Adulto , Idoso , Vértebras Cervicais/cirurgia , Feminino , Humanos , Disco Intervertebral/diagnóstico por imagem , Disco Intervertebral/cirurgia , Quimiólise do Disco Intervertebral , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Masculino , Pessoa de Meia-Idade , Radiografia Intervencionista/instrumentação , Radiografia Intervencionista/métodos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodosRESUMO
The shape, the typical orientation, and the average size of mineral crystals in different types of mineralized tissues were investigated by means of small-angle x-ray scattering (SAXS). To rule out eventual artifacts due to sample preparation, four different standard preparation techniques were used and a comparison showed that the SAXS results were identical for all four methods. In mineralized turkey leg tendon, a frequently used model system for bone, the crystals were found to be typically plate-like with a thickness of the order of 2 nm. This stands in contrast to the case of bone (calvaria, femur, and iliac crest) from mouse, rat, and dog, where mainly needle-like crystals were found. The thickness of these crystals ranged from 3 to 4 nm but was remarkably constant for different bones of a given animal. The preferred orientation of the needle-like crystals was along the main axis of the femur and within the surface of the calvaria (for mouse, rat, and dog). The mineral plates in turkey leg tendon were located inside the hole zone and oriented along the fibril axis. Finally, no periodic arrangement of the crystals inside the hole zone of the collagen could be found.
Assuntos
Osso e Ossos/química , Calcificação Fisiológica/fisiologia , Minerais/química , Tendões/química , Animais , Cristalização , Cães , Camundongos , Ratos , Espalhamento de Radiação , Manejo de Espécimes/métodos , PerusRESUMO
A CT assisted method for automated percutaneous lumbar discectomy (APLD) is described. With this technique and introduction of a "pull and push" method as well extruded and sequestrated herniated lumbar discs as cervical herniated discs can be treated. The CT assisted discectomy was performed in 70 patients. The success rate was 86% in the lumbar region and 93% for cervical herniated discs. We believe that this percutaneous technique will increase the importance of interventional neuroradiology for this common disease.
Assuntos
Endoscópios , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Técnicas Estereotáxicas/instrumentação , Tomografia Computadorizada por Raios X/instrumentação , Adulto , Idoso , Desenho de Equipamento , Feminino , Seguimentos , Humanos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Recidiva , Instrumentos CirúrgicosRESUMO
Ever since the causal relationship between backache, radicular pain and intravertebral disc herniation was established [25], there have been different opinions about the degree of recovery of motor lesions of the nerve root caused by disc herniation. Of 123 patients with a severe motor deficit of the L5 nerve root, 95 patients were available for a follow up examination 4 to 8 years after the operation. The statistical evaluation showed that the degree of recovery of the root lesion was mainly dependent on the age of the patient and the time interval until operation. Even a prior herniation of the disc without much compression of the nerve root can cause chronic damage to the nerve through traction at the trilamellar nerve root fixation. So even in the case of only a small disc hernia with a corresponding nerve root lesion, we would recommend immediate operative therapy.
Assuntos
Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Síndromes de Compressão Nervosa/cirurgia , Exame Neurológico , Complicações Pós-Operatórias/fisiopatologia , Raízes Nervosas Espinhais/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Deslocamento do Disco Intervertebral/fisiopatologia , Laminectomia , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Síndromes de Compressão Nervosa/fisiopatologia , Raízes Nervosas Espinhais/fisiopatologiaRESUMO
The mechanism of calcification in bone and related tissues is a matter of current interest. The mean size and the arrangement of the mineral crystals are important parameters difficult to obtain by electron microscopy. Furthermore, most studies have been carried out on poorly calcified model systems or chemically treated samples. In the work presented here, native bone was studied as a function of age by a quantitative small-angle X-ray scattering method (SAXS). Bone samples (calvariae and ulnae) from rats and mice were investigated. Measurements were performed on native bone immediately after dissection for samples up to 1 mm thick. The size, shape, and predominant orientation of the mineral crystals in bone were obtained for embryonal, young, and adult animals. The results indicate that the mineral nucleates as thin layers of calcium phosphate within the hole zone of the collagen fibrils. The mineral nuclei subsequently grow in thickness to about 3 nm, which corresponds to maximum space available in these holes.
Assuntos
Densidade Óssea , Minerais/química , Animais , Fosfatos de Cálcio/análise , Colágeno/análise , Cristalização , Camundongos , Minerais/metabolismo , Radiografia , Ratos , Espalhamento de Radiação , Crânio/química , Crânio/diagnóstico por imagem , Crânio/metabolismo , Ulna/química , Ulna/diagnóstico por imagem , Ulna/metabolismo , Raios XRESUMO
In effort to eliminate morbidity and costs, associated with arteriographic investigation, we increasingly perform Duplex Scan of the extracranial carotid artery prior to endarterectomy. 451 carotid reconstructions between 1986 and April 1991 were evaluated retrospectively. The percentage of patients undergoing carotid endarterectomy without angiography has increased from 21.1% to 92.8%. Angiography was associated with a combined neurologic morbidity rate of 3.0%. Perioperative outcome of patients and stratification by indication did not show any significant differences for both groups undergoing Duplex Scan alone and/or angiography. Diagnostic Carotid angiography should only be used selectively in patients showing distal internal carotid plaque, recurrent stenosis, symptomatic carotid occlusion or aortic arch disease.