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1.
Phys Rev Lett ; 119(22): 226401, 2017 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-29286805

RESUMEN

We study the electronic transport across an electrostatically gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without an applied magnetic field. We control the carrier density inside and outside a junction region independently and hence tune the number and nature of 1D edge modes propagating in each of those regions. Outside the bulk gap, the magnetic field drives the system to the quantum Hall regime, and chiral states propagate at the edge. In this regime, we observe fractional plateaus that reflect the equilibration between 1D chiral modes across the junction. As the carrier density approaches zero in the central region and at moderate fields, we observe oscillations in the resistance that we attribute to Fabry-Perot interference in the helical states, enabled by the broken time reversal symmetry. At higher fields, those oscillations disappear, in agreement with the expected absence of helical states when band inversion is lifted.

2.
Sci Rep ; 5: 18380, 2015 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-26681110

RESUMEN

Spatially-resolved neutron powder diffraction with a gauge volume of 2 × 2 × 20 mm(3) has been applied as an in situ method to probe the lithium concentration in the graphite anode of different Li-ion cells of 18650-type in charged state. Structural studies performed in combination with electrochemical measurements and X-ray computed tomography under real cell operating conditions unambiguously revealed non-homogeneity of the lithium distribution in the graphite anode. Deviations from a homogeneous behaviour have been found in both radial and axial directions of 18650-type cells and were discussed in the frame of cell geometry and electrical connection of electrodes, which might play a crucial role in the homogeneity of the lithium distribution in the active materials within each electrode.

3.
Phys Rev Lett ; 112(14): 146803, 2014 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-24766002

RESUMEN

We study the weak antilocalization (WAL) effect in the magnetoresistance of narrow HgTe wires fabricated in quantum wells with normal and inverted band ordering. Measurements at different gate voltages indicate that the WAL is only weakly affected by Rashba spin-orbit splitting and persists when the Rashba splitting is about zero. The WAL amplitude in wires with normal band ordering is an order of magnitude smaller than for wires with an inverted band structure. These observations are attributed to the Dirac-like dispersion of the energy bands in HgTe quantum wells. From the magnetic-field and temperature dependencies we extract the dephasing lengths and band Berry phases. The weaker WAL for samples with a normal band structure can be explained by a nonuniversal Berry phase which always exceeds π, the characteristic value for gapless Dirac fermions.

4.
Phys Med Biol ; 56(1): N1-N10, 2011 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-21119223

RESUMEN

Using conventional methods, three-dimensional imaging of the lung is challenging because of the low contrast between air and tissue and the large differences in dimensions between various pulmonary structures. The small distal airway structures and the high air-to-tissue ratio of lung tissue require an imaging technique which reliably discriminates between air and water. The objective of this study was to assess whether neutron computed tomography would satisfy such a requirement. This method utilizes the unique characteristic of neutrons of directly interacting with the atomic nucleus rather than being scattered by the atomic shell. Neutron computed tomography was tested in rats and allowed differentiation of larger lung structures (e.g., lobes) and distal airways. Airways could be identified reliably down to the sixth bronchial generation, in some cases even down to the tenth generation. The lung could be stabilized for sufficiently long exposure times to achieve an image resolution of 50-60 µm, which is the current physical resolution limit of the neutron computed tomography facility. Neutron computed tomography allowed excellent lung imaging without the need for additional tissue preparation or contrast media. The enhanced structural resolution obtained by applying this new research technique may improve understanding of lung physiology and respiratory therapy.


Asunto(s)
Pulmón/diagnóstico por imagen , Neutrones , Tomografía Computarizada por Rayos X/métodos , Animales , Bronquios/patología , Bronquios/fisiología , Pulmón/fisiología , Masculino , Modelos Animales , Ratas , Ratas Wistar , Mecánica Respiratoria
5.
Acta Neurochir (Wien) ; 149(10): 983-90; discussion 990, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17676411

RESUMEN

OBJECTIVES: Normal-pressure hydrocephalus (NPH) syndrome is treatable by implantation of a cerebrospinal fluid (CSF) shunt. However, diagnosis of NPH by clinical and radiological findings alone is unreliable, and co-existing structural dementia can contribute to low success rates after shunt implantation. The aim of our study was to investigate whether long-term results after shunt implantation in NPH improve when surgical candidates are selected by continuous intraventricular pressure monitoring (CIPM). PATIENTS AND METHODS: Ninety-two consecutive patients who were admitted with suspected NPH received CIPM for 48 h including an intraventricular steady-state infusion test to determine the resistance outflow. With positive CIPM, shunt implantation was performed and the patients were prospectively followed up for 1 to 10 years (median 6.5 years). RESULTS: CIPM was negative in 37 patients. Fifty-five patients had a positive CIPM and received CSF shunt. 96.1% of them improved from gait disturbance, 77.1% from cognitive impairment and 75.7% from urinary dysfunction. Clinical improvement remained during long-term follow-up in all but 3 patients who showed a decline at 4, 5 and 7 years, respectively. CIPM-related complications (ventriculitis) occurred in only one patient. CONCLUSION: CIPM is a safe and valuable tool to establish a reliable diagnosis of NPH and to identify promising surgical candidates.


Asunto(s)
Hidrocéfalo Normotenso/diagnóstico , Presión Ventricular/fisiología , Derivaciones del Líquido Cefalorraquídeo , Demencia/etiología , Demencia/cirugía , Estudios de Seguimiento , Trastornos Neurológicos de la Marcha/etiología , Trastornos Neurológicos de la Marcha/cirugía , Humanos , Hidrocéfalo Normotenso/etiología , Hidrocéfalo Normotenso/fisiopatología , Hidrocéfalo Normotenso/cirugía , Imagen por Resonancia Magnética , Monitoreo Fisiológico , Examen Neurológico , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/fisiopatología , Estudios Prospectivos , Recurrencia , Punción Espinal , Tomografía Computarizada por Rayos X , Incontinencia Urinaria/etiología , Incontinencia Urinaria/cirugía
6.
Braz J Med Biol Res ; 39(2): 289-95, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16470318

RESUMEN

The present study was carried out to assess the possibility of measuring fecal steroid hormone metabolites as a noninvasive technique for monitoring reproductive function in the three-toed sloth, Bradypus variegatus. Levels of the estradiol (E2) and progesterone (P4) metabolites were measured by radioimmunoassay in fecal samples collected over 12 weeks from 4 captive female B. variegatus sloths. The validation of the radioimmunoassay for evaluation of fecal steroid metabolites was carried out by collecting 10 blood samples on the same day as defecation. There was a significant direct correlation between the plasma and fecal E2 and P4 levels (P < 0.05, Pearson's test), thereby validating this noninvasive technique for the study of the estrous cycle in these animals. Ovulation was detected in two sloths (SL03 and SL04) whose E2 levels reached 2237.43 and 6713.26 pg/g wet feces weight, respectively, for over four weeks, followed by an increase in P4 metabolites reaching 33.54 and 3242.68 ng/g wet feces weight, respectively. Interestingly, SL04, which presented higher levels of E2 and P4 metabolites, later gave birth to a healthy baby sloth. The results obtained indicate that this is a reliable technique for recording gonadal steroid secretion and thereby reproduction in sloths.


Asunto(s)
Estradiol/análisis , Ciclo Estral/metabolismo , Heces/química , Progesterona/análisis , Perezosos/metabolismo , Animales , Ciclo Estral/fisiología , Femenino , Radioinmunoensayo , Perezosos/fisiología
7.
Braz. j. med. biol. res ; 39(2): 289-295, Feb. 2006. graf
Artículo en Inglés | LILACS | ID: lil-420282

RESUMEN

The present study was carried out to assess the possibility of measuring fecal steroid hormone metabolites as a noninvasive technique for monitoring reproductive function in the three-toed sloth, Bradypus variegatus. Levels of the estradiol (E2) and progesterone (P4) metabolites were measured by radioimmunoassay in fecal samples collected over 12 weeks from 4 captive female B. variegatus sloths. The validation of the radioimmunoassay for evaluation of fecal steroid metabolites was carried out by collecting 10 blood samples on the same day as defecation. There was a significant direct correlation between the plasma and fecal E2 and P4 levels (P < 0.05, Pearson's test), thereby validating this noninvasive technique for the study of the estrous cycle in these animals. Ovulation was detected in two sloths (SL03 and SL04) whose E2 levels reached 2237.43 and 6713.26 pg/g wet feces weight, respectively, for over four weeks, followed by an increase in P4 metabolites reaching 33.54 and 3242.68 ng/g wet feces weight, respectively. Interestingly, SL04, which presented higher levels of E2 and P4 metabolites, later gave birth to a healthy baby sloth. The results obtained indicate that this is a reliable technique for recording gonadal steroid secretion and thereby reproduction in sloths.


Asunto(s)
Animales , Femenino , Estradiol/análisis , Ciclo Estral/metabolismo , Heces/química , Progesterona/análisis , Perezosos/metabolismo , Ciclo Estral/fisiología , Radioinmunoensayo , Perezosos/fisiología
8.
Eur J Med Res ; 10(12): 509-14, 2005 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-16356865

RESUMEN

BACKGROUND: Alpha-1-antitrypsin (alpha1-AT) is an important protease inhibitor. The phenotypes are characterized by a low total serum alpha1-AT or by an abnormal protein accumulating in the hepatocytes. The aim of our study was to examine a correlation of total serum alpha1-AT, phenotype, and liver involvement in pediatric patients. METHODS: 48 patients, deficient for alpha1-AT were included. The phenotypes for alpha1-AT were determined by isoelectric focusing. Liver disease was defined either as elevated transaminases or/and as elevated conjugated bilirubin and gammaGT. Patients were reexamined after a mean interval of 2 years. RESULTS: Homozygous alpha1-AD was found in 12 patients, heterozygous in 24 patients. In 12 children rare variants of alpha1-AD were diagnosed. Serum alpha1-AT levels less than 60% of normal were found in all patients with homozygous, in 37% of patients with heterozygous alpha1-antitrypsin deficiency (alpha1-AD), and in patients with the homozygous variant PiM(palermo). Liver disease was found in 8/12 patients with the phenotype PiZZ and in 15/24 patients with heterozygous alpha1-AD. Three of 4 patients with the phenotype PiMQ0 had severe liver disease despite normal serum levels for alpha1-AT. In 11 patients with heterozygous alpha1-AD liver disease was apparent despite normal serum alpha1-AT levels. In two patients with the variant type Mpalermo serum levels were as low as 11% of normal without any signs of liver disease. CONCLUSIONS: Our data clearly show that in the diagnostic workup of neonatal cholestasis measurement of total serum alpha1-AT does not exclude liver disease due to abnormal alpha1-AT variants. We suggest analysis of alpha1-AT-phenotype by isoelectric focussing in patients with unknown liver disease. Heterozygous or rare variant types might remain undiagnosed by measuring total alpha1-AT only.


Asunto(s)
Hepatopatías/sangre , Deficiencia de alfa 1-Antitripsina/sangre , alfa 1-Antitripsina/análisis , Adolescente , Niño , Preescolar , Colestasis/sangre , Colestasis/etiología , Colestasis/patología , Femenino , Genotipo , Hepatitis/sangre , Hepatitis/etiología , Hepatitis/patología , Humanos , Lactante , Recién Nacido , Focalización Isoeléctrica , Cirrosis Hepática/sangre , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Hepatopatías/etiología , Hepatopatías/patología , Pruebas de Función Hepática , Masculino , Fenotipo , Estudios Retrospectivos , alfa 1-Antitripsina/química , Deficiencia de alfa 1-Antitripsina/complicaciones , Deficiencia de alfa 1-Antitripsina/patología
9.
World J Gastroenterol ; 11(38): 6031-7, 2005 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-16273620

RESUMEN

AIM: Clinical and experimental data suggest that gut-derived endotoxins are an important pathogenic factors for progression of chronic liver disease. Recently, a C-T (-159) polymorphism in the promoter region of the CD14 gene was detected and found to confer increased CD14 expression and to be associated with advanced alcoholic liver damage. Here, we investigated this polymorphism in patients with less advanced alcoholic liver disease (ALD) and chronic hepatitis C virus (HCV) infection. METHODS: CD14 genotyping was performed by PCR-RFLP analysis in (a) 121 HCV patients, (b) 62 patients with alcohol-associated cirrhosis (Alc-Ci), (c) 118 individuals with heavy alcohol abuse without evidence of advanced liver damage (Alc-w/o Ci), and (d) 247 healthy controls. Furthermore, serum levels of soluble CD14 (sCD14) and transaminases were determined. RESULTS: The TT genotype was significantly more frequent in Alc-Ci compared to Alc-w/o Ci or controls (40.3% vs 23.7% or 24.0%, respectively). In Alc-w/o Ci, serum levels of transaminases did not differ significantly between patients with different CD14 genotypes. In HCV patients, TT-homozygotes had significantly higher sCD14 levels and sCD14 serum levels were significantly higher in patients with advanced fibrosis or cirrhosis. However, no association was found between CD14 genotypes and histological staging or grading. CONCLUSION: Considering serum transaminases as surrogate markers for alcoholic liver damage, the CD14 polymorphism seems to exhibit different effects during the course of ALD. Differences in genotype distribution between cirrhotic HCV patients and alcoholics and the known functional impact of this polymorphism on CD14 expression levels further indicate differences in the pathophysiological role of CD14 and CD14-mediated lipopolysaccharides signal transduction with regard to the stage as well as the type of the underlying liver disease.


Asunto(s)
Hepatitis C Crónica/genética , Hepatitis C Crónica/inmunología , Receptores de Lipopolisacáridos/genética , Hepatopatías Alcohólicas/genética , Hepatopatías Alcohólicas/inmunología , Adulto , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Genotipo , Humanos , Receptores de Lipopolisacáridos/sangre , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Estudios Retrospectivos
10.
Am J Physiol Gastrointest Liver Physiol ; 286(6): G1000-8, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-14726307

RESUMEN

Several effects of bile acids (BAs) on colonic epithelial cells (CECs) have been described, including induction of proliferation and apoptosis. Some of these effects are mediated through activation of the NF-kappa B transcriptional system. In this study, we investigated the molecular mechanisms underlying the BA-induced gene expression in CECs. The human CEC line HT-29 and primary human CECs were treated with dilutions of salts of deoxycholic acid (DCA) and taurodeoxycholic acid (TDCA). NF-kappa B binding activity was analyzed with EMSA, RelA translocation with immunofluorescence, and I kappa B alpha- and RelA-phosphorylation with Western blot analysis. IL-8 mRNA and protein expression were assessed by quantitative PCR and ELISA. Functional impact of NF-kappa B activation was determined by blocking the proteasome activity with MG132 or by preventing IKK activity with a dominant-negative IKK beta delivered by adenoviral dominant-negative (dn) IKK beta (Ad5dnIKK beta). DCA and TDCA induced IL-8 expression in a dose- and time-dependent manner. It is interesting that DCA but not TDCA induced I kappa B alpha-phosphorylation, RelA translocation, and NF-kappa B binding activity. Accordingly, the proteasome inhibitor MG132 blocked DCA- but not TDCA-induced IL-8 gene expression. In contrast, TDCA-induced IL-8 gene expression correlated with enhanced RelA phosphorylation, which was blocked by Ad5dnIKK beta. Our data suggest that DCA-induced signal transduction mainly utilized the I kappa B degradation and RelA nuclear translocation pathway, whereas TDCA primarily induced IL-8 gene expression through RelA phosphorylation. These differences may have implications for the understanding of the pathophysiology of inflammation and carcinogenesis in the gut.


Asunto(s)
Colon/metabolismo , Ácido Desoxicólico/farmacología , Interleucina-8/metabolismo , Mucosa Intestinal/metabolismo , FN-kappa B/metabolismo , Transducción de Señal/efectos de los fármacos , Ácido Taurodesoxicólico/farmacología , Ácidos y Sales Biliares/farmacología , Células Cultivadas , Colon/citología , Colon/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Humanos , Interleucina-8/genética , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , ARN Mensajero/metabolismo , Factores de Tiempo
11.
J Neurol Neurosurg Psychiatry ; 74(7): 929-32, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12810782

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the influence of total drainage time on the risk of catheter infection, and the predictive value of standard laboratory examinations for the diagnosis of bacteriologically recorded cerebrospinal fluid (CSF) infection during external ventricular drainage. METHODS: During a three year period, all patients of the neurosurgical intensive care unit (ICU), who received an external ventricular drain, were prospectivly studied. Daily CSF samples were obtained and examined for cell count, glucose and protein content. Bacteriological cultures were taken three times a week, and serum sepsis parameters were determined. RESULTS: 130 patients received a total of 186 external ventricular drains. The ventricular catheters were in place from one to 25 days (mean 7.1 days). In 1343 days of drainage, the authors recorded 41 positive bacteriological cultures in 21 patients between the first and the 22nd drainage day (mean 6.4). No significant correlation was found between drainage time and positive CSF culture. The only parameter that significantly correlated with the occurrence of a positive CSF culture was the CSF cell count (unpaired t test, p<0.05). CONCLUSIONS: Drainage time is not a significant risk factor for catheter infection. Increasing CSF cell count should lead to the suspicion of bacteriological drainage contamination. Other standard laboratory parameters, such as peripheral leucocyte count, CSF glucose, CSF protein, or serum sepsis parameters, are not reliable predictors for incipient ventricular catheter infection.


Asunto(s)
Cateterismo/efectos adversos , Infecciones del Sistema Nervioso Central/diagnóstico , Infecciones del Sistema Nervioso Central/etiología , Líquido Cefalorraquídeo/microbiología , Ventriculostomía/efectos adversos , Adolescente , Adulto , Anciano , Bacterias/aislamiento & purificación , Bacterias/patogenicidad , Proteínas del Líquido Cefalorraquídeo/análisis , Niño , Preescolar , Femenino , Glucosa/líquido cefalorraquídeo , Humanos , Lactante , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Factores de Riesgo , Sepsis , Factores de Tiempo
12.
Minim Invasive Neurosurg ; 45(3): 177-80, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12353168

RESUMEN

OBJECTIVE AND IMPORTANCE: We report the very rare case of a gliomyosarcoma that caused penetration failure in stereotactic biopsy and therefore led to misdiagnosis. This complication should be considered as a potential reason for diagnostic failure with uncommonly firm tumors in frame-based stereotactic biopsy. CLINICAL PRESENTATION: An 83-year-old women presented with a 4-week history of right hemiparesis. Computed tomography (CT) demonstrated a left precentral lesion of 1 cm in diameter with moderate contrast uptake and perifocal edema. INTERVENTION: Stereotactic biopsy was performed using the Cosman-Robert-Wells (CRW) system and a side-aspirating biopsy needle. Six tissue samples were taken; however, histopathologic examination remained non-diagnostic. Because the hemiparesis had worsened, a magnetic resonance tomography (MRT) was taken four weeks later and clearly demonstrated an increase in size of the lesion. Neuronavigation-guided open surgery revealed a very firm, well-delimited tumor that was classified in the pathologic examination as a gliomyosarcoma. Repeated recalculations of the target coordinates, analysis of the CT scan that was taken 4 days after the stereotaxy, and finally, recognition of the extraordinary firmness of this gliomyosarcoma allowed us to presume with certainty that we had not penetrated the lesion with the biopsy cannula, but rather had merely pushed it ahead of the instrument while the tissue samples were taken. CONCLUSION: The reported case is both unique for its histopathologic diagnosis and for the complication it caused in stereotactic biopsy. The case also supports the implementation of image-guided interventions for diagnostic biopsy, rather than frame-based stereotaxy in the future.


Asunto(s)
Biopsia/métodos , Neoplasias Encefálicas/patología , Errores Diagnósticos , Glioma/patología , Miosarcoma/patología , Técnicas Estereotáxicas , Anciano , Anciano de 80 o más Años , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/cirugía , Femenino , Glioma/diagnóstico por imagen , Glioma/cirugía , Humanos , Miosarcoma/diagnóstico por imagen , Miosarcoma/cirugía , Neuronavegación , Procedimientos Neuroquirúrgicos , Radiografía
13.
Am J Surg Pathol ; 25(12): 1520-7, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11717542

RESUMEN

Bone cells are important targets of platelet-derived growth factors (PDGFs) because they stimulate proliferation of osteoblasts and chondrocytes. In this study we wanted to determine the expression of PDGF-AA and PDGF-alpha receptor in conventional chondrosarcomas and to compare the results with those obtained from benign enchondromas and non-neoplastic cartilage tissue. Sixty-seven chondrosarcomas, 20 enchondromas, and 5 specimens of healthy cartilage as well as 7 specimens of hypertrophic callus cartilage were immunohistochemically analyzed for the expression of PDGF-AA and PDGF-alpha receptor, respectively. Additionally, the proliferation activity was examined with the MIB-1 antibody. Clinical follow-up data were available from 53 patients. A significant overexpression of receptor and factor was found in chondrosarcomas as compared with enchondromas (PDGF-AA p = 0.013, PDGF-alpha receptor p <0.001). MIB-1 values were significantly higher in chondrosarcomas (p <0.001). In healthy joint cartilage no staining was detectable, whereas reactive cartilage of callus formation showed high expression levels. PDGF-alpha receptor expression was significantly higher in grade 3 chondrosarcomas compared with grade 2 (p = 0.022) and grade 1 tumors (p = 0.002). Survival analysis documented a significantly shorter overall survival for patients with high PDGF-alpha receptor expression (p = 0.0172, log-rank test). Because PDGF-alpha receptor expression positively correlates with the aggressiveness of chondrosarcoma, it may be considered as a possible target for novel therapeutic strategies.


Asunto(s)
Neoplasias Óseas/metabolismo , Condrosarcoma/metabolismo , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antígenos Nucleares , Neoplasias Óseas/mortalidad , Neoplasias Óseas/patología , Callo Óseo/metabolismo , Cartílago/metabolismo , Condroma/metabolismo , Condroma/patología , Condrosarcoma/mortalidad , Condrosarcoma/secundario , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Técnicas para Inmunoenzimas , Antígeno Ki-67 , Masculino , Persona de Mediana Edad , Proteínas Nucleares/análisis , Factor de Crecimiento Derivado de Plaquetas/metabolismo , Tasa de Supervivencia
14.
Z Orthop Ihre Grenzgeb ; 139(5): 435-9, 2001.
Artículo en Alemán | MEDLINE | ID: mdl-11605296

RESUMEN

AIM: A Chevron osteotomy with lateral soft-tissue release was performed at our department in 1993. In 1994 a prospective study to evaluate the temporary Kirschner wire fixation was started. Aim of this prospective study was to analyse the short-term clinical and radiological results with special attention to stability, necroses, and luxation of the first metatarsal head. METHOD: Between February 1994 and October 1995 45 patients (55 feet) were treated with a Chevron osteotomy combined with a lateral soft-tissue release and temporary Kirschner wire fixation. The average follow-up was 33.9 months. All patients were seen and evaluated preoperatively and at a minimum follow-up of 24 months using a standardized questionnaire based on the Hallux metatarsophalangeal interphalangeal Scale (HMIS) of the American Foot and Ankle Society. RESULTS: Results of the survey of patient satisfaction revealed excellent and good results in 83%, fair in 8%, and poor in 9%. The median HMIS at final follow-up was 86.9 pints of 100 points. The average hallux valgus angle correction was 19.8 (from 28.7 to 8.9) and the average first intermetatarsal angel correction was, 8.2 (from 14.4 to 6.2). No avascular necrosis of the first metatarsal head and no loss of correction were noted. In one case a luxation of the metatarsal head was observed. CONCLUSION: Combining the Chevron osteotomy with an excessive lateral soft-tissue release increases the likelihood of instability of the metatarsal head and consecutive loss of correction. The temporary Kirschner wire fixation increases the stability of the Chevron osteotomy and prevents the loss of correction. The disadvantage of this method is, that the wire has to be removed after 6 weeks.


Asunto(s)
Hilos Ortopédicos , Hallux Valgus/cirugía , Osteotomía/métodos , Adulto , Femenino , Estudios de Seguimiento , Hallux Valgus/diagnóstico por imagen , Humanos , Masculino , Huesos Metatarsianos/diagnóstico por imagen , Huesos Metatarsianos/cirugía , Persona de Mediana Edad , Radiografía , Resultado del Tratamiento
15.
Phys Rev Lett ; 87(8): 081801, 2001 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-11497934

RESUMEN

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

16.
Acta Neurochir (Wien) ; 143(4): 369-76, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11437291

RESUMEN

BACKGROUND: Anteriorly located lesions at the craniocervical junction (CCJ) require careful surgical planning to avoid neuraxis retraction. Several different routes have been described in the search for the most appropriate yet least invasive approach. However, most of these far-lateral posterior approaches are specifically tailored for non-osseous intradural tumours or chordomas with cephalad extension. We introduce an approach that allows for better access to laterally extending osseous tumours originating from the second cervical vertebra. Using this approach, the lesion is manipulated from a strictly lateral direction parallel to a plane through the articular pillar of the CCJ and the odontoid process, and the C1- and C2-laminae are spared for posterior fixation. METHOD: The application of this approach is demonstrated in detail by an illustrative case of a chordoma originating from C2 that presented with intradural mass effect, considerable bone destruction, far-lateral extension to the right, and vertebral artery involvement. FINDINGS: The described approach gave ample access for total tumour resection. It allowed for safe control and displacement of the vertebral artery, spinal cord decompression, C2-corpectomy across the midline, and anterolateral bone reconstruction. No C1- or C2-hemilaminectomy was needed, and these bone elements could be used for posterior fixation (the patient presented in this study was referred to our institution after posterior fixation from the occiput to C3 had already been performed elsewhere). No intra-operative or postoperative complications occurred. At the 6-month follow-up, the patient was fully ambulatory with no neurological deficit. INTERPRETATION: The described lateral transfacetal route is the method of choice for operating on laterally extending osseous tumours originating from the second cervical vertebra.


Asunto(s)
Vértebras Cervicales/cirugía , Cordoma/cirugía , Lateralidad Funcional , Neoplasias de Cabeza y Cuello/cirugía , Procedimientos Quirúrgicos Vasculares/métodos , Articulación Cigapofisaria/cirugía , Trasplante Óseo , Vértebras Cervicales/patología , Cordoma/patología , Descompresión Quirúrgica/métodos , Neoplasias de Cabeza y Cuello/patología , Humanos , Masculino , Persona de Mediana Edad , Arteria Vertebral/patología , Arteria Vertebral/cirugía , Articulación Cigapofisaria/patología
17.
J Neurosurg ; 93(1 Suppl): 161-7, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10879777

RESUMEN

The anterior decompressive procedure in which spinal fusion is performed is considered an effective treatment for thoracolumbar fractures and tumors. However, it is also known to be associated with considerable surgery-related trauma. The purpose of this study was to show that lumbar corpectomy and anterior reconstruction can be performed via a minimally invasive retroperitoneal approach (MIRA) and therefore the surgical approach-related trauma can be reduced. The authors studied retrospectively the hospital records and radiological studies obtained in five patients (mean age 67.4 years, range 59-76 years) who underwent lumbar corpectomy and spinal fusion via an MIRA followed by posterior fixation. Four patients presented with osteoporotic compression fractures at L-2 and L-3, and one patient presented with metastatic disease in L-4 from prostate cancer. Neurological deficits due to cauda equina compression were demonstrated in all patients. The MIRA provided excellent exposure to facilitate complete decompression and anterior reconstruction in all patients, as verified on follow-up radiographic studies. All patients improved clinically. A 1-year follow-up record is available for four patients and a 6-month follow-up record for the fifth patient; continuing clinical improvement has been observed in all. Radiography demonstrated anatomically correct reconstruction in all patients, as well as a solid fusion or a stable compound union in the four patients for whom 1-year follow-up records were available. The MIRA allows the surgeon to perform anterior lumbar spine surgery via a less invasive approach. The efficacy and safety of this technique and its potential to reduce perioperative morbidity compared with conventional retroperitoneal lumbar spine surgery should be further investigated in a larger series.


Asunto(s)
Vértebras Lumbares/cirugía , Procedimientos de Cirugía Plástica/métodos , Anciano , Trasplante Óseo , Descompresión Quirúrgica/métodos , Femenino , Estudios de Seguimiento , Humanos , Complicaciones Intraoperatorias/prevención & control , Masculino , Microcirugia/métodos , Persona de Mediana Edad , Procedimientos Quirúrgicos Mínimamente Invasivos , Síndromes de Compresión Nerviosa/cirugía , Dispositivos de Fijación Ortopédica , Osteoporosis/cirugía , Polirradiculopatía/cirugía , Neoplasias de la Próstata/patología , Espacio Retroperitoneal , Estudios Retrospectivos , Seguridad , Enfermedades de la Columna Vertebral/cirugía , Fracturas de la Columna Vertebral/cirugía , Fusión Vertebral/métodos , Neoplasias de la Columna Vertebral/secundario , Neoplasias de la Columna Vertebral/cirugía , Resultado del Tratamiento
19.
Acta Neurochir (Wien) ; 142(11): 1219-30, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11201636

RESUMEN

BACKGROUND: In noncontiguous spinal metastatic disease, anterior or combined anterior-posterior surgery is an effective treatment. The objective of this study is to investigate whether circumferential decompression through a single-stage posterior midline approach with individualized spinal reconstruction can still achieve comparable results for functional improvement and for maintenance of spinal alignment in the absence of the risks associated with the more invasive transcavitary or combined approaches. METHOD: Seventeen patients with noncontiguous spinal metastases and plasmocytomas at one or two adjacent levels were included in this series. Circumferential decompression was obtained with anterior reconstruction and posterior fixation in ten patients, and with posterior instrumentation alone in seven patients. Postoperatively the patients were prospectively followed, and their functional status and spinal alignment were periodically evaluated. FINDINGS: Fourteen patients died from progression of their underlying cancer. Their mean survival time was 8 months (range: 1 to 21 months). Three survivors were evaluated at 10, 4 and 3 months respectively. At one month after surgery, 14 patients (82%) showed neurological improvement. Of 10 preoperative nonambulators, seven regained walking capacity. Five patients who were ambulatory with assistance improved to full functional independence. Local tumour recurrence was recorded in one patient after subtotal vertebrectomy for a plasmocytoma at L5. No other tumour recurrences were noted. In one patient a partial loss of correction occurred at T6 - without functional deterioration, however. Spinal alignment was maintained in all other patients who became or remained ambulatory. No major intra-operative complications or peri-operative deaths occurred. CSF leakage was recorded as the most common complication in four patients. INTERPRETATION: Circumferential decompression and spinal reconstruction through a single-stage posterior midline approach is feasible and effective. The extent of surgery can be individualized by means of this technique to the patient's specific problem. In patients with limited life expectancy from metastatic neoplastic disease, the results compare favourably with the more invasive anterior or combined antero-posterior procedures.


Asunto(s)
Plasmacitoma/cirugía , Procedimientos de Cirugía Plástica/métodos , Neoplasias de la Médula Espinal/secundario , Neoplasias de la Médula Espinal/cirugía , Adulto , Anciano , Placas Óseas , Tornillos Óseos , Descompresión Quirúrgica/métodos , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Estudios Prospectivos , Médula Espinal/patología , Médula Espinal/cirugía , Columna Vertebral/patología , Columna Vertebral/cirugía , Resultado del Tratamiento
20.
Z Orthop Ihre Grenzgeb ; 137(5): 452-6, 1999.
Artículo en Alemán | MEDLINE | ID: mdl-10549125

RESUMEN

INTRODUCTION: The aim of this retrospective study was to analyse the short term results after the Weil-procedure for the treatment for metatarsalgia in 30 consecutive patients. METHODS: 30 patients (69 osteotomies) after the Weil-procedure with an average age of 60 years (range 25 to 78 years) were analysed by clinical and radiological evaluation. The average follow up was 15 months (range 12 to 26 months). Analysis was performed using the patients' records, weight-bearing radiographs and a standardized questionnaire. RESULTS: Subjective evaluation revealed 23 very satisfied and satisfied patients. Based on the Lesser-Metatarsal-Interphalangeal-Scale the objective results showed 77.1 points on average. The results were excellent in 17 cases, good in 4, fair in 3 and unsatisfactory in 6 cases respectively. Recurrent metatarsalgia was noted in 5 cases, whereas no transfermetatarsalgia was observed. The average shortening was 4.4 mm. Subluxation of the metatarsophalangeal joint was corrected in 18 out of 22 cases. A restricted plantar flexion of the metatarsophalangeal joint was noted in 14 cases. 2 patients showed loss of movement. CONCLUSION: Our short-term results reveal that the Weil-osteotomy is a sufficient treatment for metatarsalgia. This technique is able to reestablish the alignment of the metatarsals and to correct luxation and subluxation of the metatarsophalangeal joint. Restricted plantarflexion of the metatarsophalangeal joint is a drawback, which may be avoided by intensive physiotherapy.


Asunto(s)
Articulación Metatarsofalángica/cirugía , Osteotomía/métodos , Adulto , Anciano , Tornillos Óseos , Femenino , Humanos , Luxaciones Articulares/diagnóstico por imagen , Luxaciones Articulares/cirugía , Masculino , Articulación Metatarsofalángica/diagnóstico por imagen , Articulación Metatarsofalángica/lesiones , Persona de Mediana Edad , Dimensión del Dolor , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/etiología , Radiografía , Recurrencia , Resultado del Tratamiento
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