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1.
Phys Med Biol ; 69(9)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38527376

RESUMEN

Objective.Task-adapted image reconstruction methods using end-to-end trainable neural networks (NNs) have been proposed to optimize reconstruction for subsequent processing tasks, such as segmentation. However, their training typically requires considerable hardware resources and thus, only relatively simple building blocks, e.g. U-Nets, are typically used, which, albeit powerful, do not integrate model-specific knowledge.Approach.In this work, we extend an end-to-end trainable task-adapted image reconstruction method for a clinically realistic reconstruction and segmentation problem of bone and cartilage in 3D knee MRI by incorporating statistical shape models (SSMs). The SSMs model the prior information and help to regularize the segmentation maps as a final post-processing step. We compare the proposed method to a simultaneous multitask learning approach for image reconstruction and segmentation (MTL) and to a complex SSMs-informed segmentation pipeline (SIS).Main results.Our experiments show that the combination of joint end-to-end training and SSMs to further regularize the segmentation maps obtained by MTL highly improves the results, especially in terms of mean and maximal surface errors. In particular, we achieve the segmentation quality of SIS and, at the same time, a substantial model reduction that yields a five-fold decimation in model parameters and a computational speedup of an order of magnitude.Significance.Remarkably, even for undersampling factors of up toR= 8, the obtained segmentation maps are of comparable quality to those obtained by SIS from ground-truth images.


Asunto(s)
Aprendizaje Profundo , Imagenología Tridimensional , Imagen por Resonancia Magnética , Imagen por Resonancia Magnética/métodos , Humanos , Imagenología Tridimensional/métodos , Articulación de la Rodilla/diagnóstico por imagen , Rodilla/diagnóstico por imagen
2.
Phys Med Biol ; 66(9)2021 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-33770783

RESUMEN

In this work, we consider the task of image reconstruction in 2D radial cardiac cine MRI using deep learning (DL)-based regularization. As the regularization is achieved by employing an image-prior predicted by a pre-trained convolutional neural network (CNN), the quality of the image-prior is of essential importance. The achievable performance of any DL-based method is limited by the amount and the quality of the available training data. For fast dynamic processes, obtaining good-quality MR data is challenging because of technical and physiological reasons. In this work, we try to overcome these problems by a transfer-learning approach which is motivated by a previously presented DL-method (XT,YT U-Net). There, instead of training the network on the whole 2D dynamic images, it is trained on 2D spatio-temporal profiles (xt,yt-slices) which show the temporal changes of the imaged object. Therefore, for the training and test data, it is more important that their spatio-temporal profiles share similar local features rather than being images of the same anatomy. This allows us to equip arbitrary data with simulated motion that resembles the cardiac motion and use it as training data. By doing so, it is possible to train a CNN which is applicable to cardiac cine MR data without using ground-truth cine MR images for training. We demonstrate that combining XT,YT U-Net with the proposed transfer-learning strategy delivers comparable performance to CNNs trained on cardiac cine MR images and in some cases even qualitatively surpasses these. Additionally, the transfer-learning strategy was investigated for a 2D and 3D U-Net. The images processed by the the CNNs were used as image-priors in the CNN-regularized iterative reconstruction. The XT,YT U-Net yielded visibly better results than the 2D U-Net and slightly better results than the 3D U-Net when used in combination with the presented transfer learning-strategy.


Asunto(s)
Aprendizaje Profundo , Imagen por Resonancia Cinemagnética , Artefactos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética
3.
Phys Med Biol ; 65(13): 135003, 2020 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-32492660

RESUMEN

In this paper we present a generalized Deep Learning-based approach for solving ill-posed large-scale inverse problems occuring in medical image reconstruction. Recently, Deep Learning methods using iterative neural networks (NNs) and cascaded NNs have been reported to achieve state-of-the-art results with respect to various quantitative quality measures as PSNR, NRMSE and SSIM across different imaging modalities. However, the fact that these approaches employ the application of the forward and adjoint operators repeatedly in the network architecture requires the network to process the whole images or volumes at once, which for some applications is computationally infeasible. In this work, we follow a different reconstruction strategy by strictly separating the application of the NN, the regularization of the solution and the consistency with the measured data. The regularization is given in the form of an image prior obtained by the output of a previously trained NN which is used in a Tikhonov regularization framework. By doing so, more complex and sophisticated network architectures can be used for the removal of the artefacts or noise than it is usually the case in iterative NNs. Due to the large scale of the considered problems and the resulting computational complexity of the employed networks, the priors are obtained by processing the images or volumes as patches or slices. We evaluated the method for the cases of 3D cone-beam low dose CT and undersampled 2D radial cine MRI and compared it to a total variation-minimization-based reconstruction algorithm as well as to a method with regularization based on learned overcomplete dictionaries. The proposed method outperformed all the reported methods with respect to all chosen quantitative measures and further accelerates the regularization step in the reconstruction by several orders of magnitude.


Asunto(s)
Diagnóstico por Imagen , Procesamiento de Imagen Asistido por Computador/métodos , Redes Neurales de la Computación , Artefactos , Tomografía Computarizada de Haz Cónico , Humanos , Fantasmas de Imagen , Dosis de Radiación , Relación Señal-Ruido
4.
Schmerz ; 21(1): 15-8, 20-4, 26-7, 2007 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-17109113

RESUMEN

Intraspinal drug infusion using implantable pumps and catheter systems is a safe and effective therapy for selected pain patients with severe chronic pain. It improves pain relief, reduces drug-related side effects, decreases the need for oral analgesia and enhances quality of life in a segment of chronic pain patients whose pain has not been controlled with more conservative therapies. Intrathecal drug therapy has therefore established its role in the treatment of malignant pain, benign pain and severe spasticity.Careful patient selection and management as well as a multidisciplinary approach are determinants of successful treatment. Current practices for patient selection and management, screening, drug selection, dosing and implantation for intrathecal drug delivery systems are discussed.


Asunto(s)
Analgesia Epidural/métodos , Dolor/tratamiento farmacológico , Analgesia Epidural/psicología , Analgésicos Opioides/administración & dosificación , Analgésicos Opioides/efectos adversos , Animales , Enfermedad Crónica , Humanos , Bombas de Infusión Implantables/psicología , Espasticidad Muscular/tratamiento farmacológico , Espasticidad Muscular/psicología , Dolor/psicología , Dimensión del Dolor/psicología , Calidad de Vida/psicología
5.
Br J Cancer ; 95(11): 1598-602, 2006 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-17106439

RESUMEN

Infections with hepatitis C virus (HCV) and, possibly, hepatitis B virus (HBV) are associated with an increased risk of non-Hodgkin's lymphoma (NHL) in the general population, but little information is available on the relationship between hepatitis viruses and NHL among people with HIV (PHIV). We conducted a matched case-control study nested in the Swiss HIV Cohort Study (SHCS). Two hundred and ninety-eight NHL cases and 889 control subjects were matched by SHCS centre, gender, age group, CD4+ count at enrollment, and length of follow-up. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were computed using logistic regression to evaluate the association between NHL and seropositivity for antibodies against HCV (anti-HCV) and hepatitis B core antigen (anti-HBc), and for hepatitis B surface antigen (HBsAg). Anti-HCV was not associated with increased NHL risk overall (OR = 1.05; 95% CI: 0.63-1.75), or in different strata of CD4+ count, age or gender. Only among men having sex with men was an association with anti-HCV found (OR = 2.37; 95% CI: 1.03-5.43). No relationships between NHL risk and anti-HBc or HBsAg emerged. Coinfection with HIV and HCV or HBV did not increase NHL risk compared to HIV alone in the SHCS.


Asunto(s)
Infecciones por VIH/complicaciones , Hepatitis C/complicaciones , Linfoma no Hodgkin/epidemiología , Adulto , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Hepacivirus , Hepatitis B/complicaciones , Virus de la Hepatitis B , Homosexualidad Masculina , Humanos , Linfoma no Hodgkin/complicaciones , Linfoma no Hodgkin/virología , Masculino , Persona de Mediana Edad , Factores de Riesgo , Suiza
6.
J Endocrinol ; 178(1): 19-27, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12844332

RESUMEN

Glucocorticoid (GC) resistance is a phenomenon of major significance in a number of clinical situations, including the therapy of lymphoid malignancies. Resistance may concern all, or just selected, GC effects, it may be absolute or just reflect a state of reduced sensitivity and, clinically relevant, be reversible or irreversible. Numerous molecular mechanisms can be envisaged acting either 'upstream' in the GC-triggered signaling pathway, i.e. at the level of the GC receptor (GR), or 'downstream' at the level of the GC-regulated genes responsible for individual GC effects. In lymphoid malignancies, GCs have anti-leukemic effects through the induction of apoptosis and/or cell cycle arrest. In this condition evidence for only a small number of mechanisms for GC resistance has been provided, mostly at the level of the GR. Herein, we review reports and hypotheses regarding 'upstream' and 'downstream' mechanisms for GC resistance in lymphoblastic leukemia and present an in vitro GC resistance model that might allow identification of resistance mechanisms.


Asunto(s)
Glucocorticoides/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Línea Celular , Resistencia a Medicamentos , Humanos , Modelos Biológicos , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo
7.
Am Surg ; 67(11): 1096-7, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11730228

RESUMEN

Ischemic vascular disease of the upper extremity represents a difficult therapeutic problem wherein medical treatment often fails. Epidural spinal cord stimulation has been shown to be an effective alternative in severe peripheral arterial disease. Although this method has been used for nearly two decades only limited experience exists in Raynaud's phenomenon of the upper limbs. In addition objective parameters to prove therapeutic success are not well defined. Herein we describe a patient with severe primary Raynaud's phenomenon over several years who had significant pain relief and complete healing of ischemic digital ulcerations after spinal cord stimulation. Pain level was evaluated using a visual rating scale before and after surgery. Microcirculatory parameters were assessed before and after spinal cord stimulation by capillary microscopy and laser Doppler anemometry. Significant improvement of red blood cell velocity, capillary density, and capillary permeability was demonstrated. At follow-up 18 months after surgery the patient had no complaints and all ulcerations of her fingertips had healed. Spinal cord stimulation appears to be an effective treatment in severe cases of Raynaud's phenomenon and we recommend its use in the case of failed medical therapy. Pain rating and capillary microscopy enable one to assess and visualize the effects of spinal cord stimulation.


Asunto(s)
Terapia por Estimulación Eléctrica , Enfermedad de Raynaud/terapia , Médula Espinal , Anciano , Femenino , Humanos
8.
Intensive Care Med ; 27(8): 1426-8, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11511960

RESUMEN

OBJECTIVE: To report the feasibility of craniectomy with duraplasty in four patients with life-threatening encephalitis and, in particular, their long-term outcome. DESIGN: Report of four cases, analysis of the acute clinical course and neurological long-term sequelae. RESULTS: Generous craniectomy with duraplasty was performed in four patients with life-threatening encephalitis leading to decortication and decerebration. This treatment approach reduced intracranial pressure. The long-term sequelae (1.5-8 years after craniectomy) confirmed its appropriateness, having led to full neurological (cerebral) function, resocialization, and reintegration into their professional life in all four patients. CONCLUSION: Craniectomy with dural augmentation is a treatment approach in cases of severe space-occupying encephalitis, not only saving the patient's life but also leading to favorable long-term outcome.


Asunto(s)
Edema Encefálico/cirugía , Craneotomía , Descompresión Quirúrgica/métodos , Encefalitis Viral/cirugía , Infecciones por Herpesviridae/cirugía , Leucoencefalitis Hemorrágica Aguda/cirugía , Adolescente , Adulto , Edema Encefálico/etiología , Encefalitis Viral/complicaciones , Femenino , Infecciones por Herpesviridae/complicaciones , Humanos , Leucoencefalitis Hemorrágica Aguda/complicaciones , Masculino
9.
Epilepsia ; 42(1): 133-5, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11207797

RESUMEN

Effective treatment of deep wound infection without removal of a previously implanted foreign body is difficult. The Neurocybernetic Prosthesis (NCP) System (Cyberonics Inc., Webster, TX, U.S.A.), implanted for vagus nerve stimulation in patients with medically refractory epilepsy, uses coil-like electrodes placed around the left vagus nerve after exposure of the nerve in the carotid sheath. Infection within this compartment endangers the contained structures and makes removal of the system hazardous. We report the case of one patient implanted with the NCP who underwent successful open wound treatment without removal of the system. A 35-year-old man had local signs of wound infection 5 weeks after implantation of a vagus nerve stimulator. Systemic signs of infection were absent. C-reactive protein was slightly elevated, but all other laboratory values were normal. After open wound debridement and thorough rinsing with bacitracin-containing solution, the wound was packed with 3% iodoformized gauze. The NCP was left in place. Systemic antibiotic therapy with fosfomycin and cefmenoxim was started. Cultures confirmed an infection with Staphylococcus aureus. The wound was rinsed daily with 3% hydrogen peroxide solution and 5% saline until cultures were sterile and granulation tissue started to fill the wound. Delayed primary closure was performed 2 weeks later. Wound healing was accomplished without removal of the device. No signs of recurrent infection were observed during a follow-up of 1 year. Open wound treatment without removal of the implanted vagus nerve stimulator is feasible in cases of deep cervical wound infection and can be an alternative if removal of the device appears hazardous.


Asunto(s)
Terapia por Estimulación Eléctrica/efectos adversos , Epilepsia/terapia , Infección de la Herida Quirúrgica/etiología , Infección de la Herida Quirúrgica/terapia , Nervio Vago/fisiología , Adulto , Antibacterianos/uso terapéutico , Remoción de Dispositivos/estadística & datos numéricos , Terapia por Estimulación Eléctrica/instrumentación , Electrodos Implantados/efectos adversos , Electrodos Implantados/microbiología , Contaminación de Equipos , Hospitalización , Humanos , Tiempo de Internación , Masculino , Prótesis e Implantes/efectos adversos , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/etiología , Infección de la Herida Quirúrgica/tratamiento farmacológico
10.
Wien Klin Wochenschr ; 111(19): 802-9, 1999 Oct 15.
Artículo en Alemán | MEDLINE | ID: mdl-10568011

RESUMEN

INTRODUCTION: The intensive care physician is frequently confronted with the decision to withhold or withdraw therapy in patients with a poor prognosis. Apart from the legal implications, the practical management of withholding or withdrawing intensive care treatment continues to be indistinct. The subject has not been investigated in Austria or Germany. The aim of the study was to examine the different points of view of intensive care physicians and the various procedures to limit therapy in patients with a poor prognosis. METHODS: We interviewed physicians working at different intensive care departments of the University Hospital of Innsbruck from March to April 1998. RESULTS: Withholding treatment was given preference over withdrawing treatment. In regard of withdrawing treatment, 64% of the interviewed physicians felt more uncertain. In the decision making process the potential reversibility of disease was estimated to be more important than the wish of the patient. Hemofiltration and antibiotics were mentioned as the first measures the physicians would withdraw. The last measure that would be withheld was ventilatory support. Sixty-three per cent of the physicians felt that sedation and analgesia should be continued. In regard of withholding or withdrawing treatment 83% voted for an obligatory DNR order. CONCLUSION: Before withholding or withdrawing intensive care therapy, a medical specialist must determine and document the futile prognosis of the patient. If the patient's wish is unknown, all further decisions should be made in agreement with all participants. The goal of the therapy is to provide the patient maximum comfort under minimal intensive care treatment.


Asunto(s)
Actitud del Personal de Salud , Eutanasia Pasiva , Unidades de Cuidados Intensivos , Austria , Hospitales Universitarios , Humanos , Cuerpo Médico de Hospitales , Órdenes de Resucitación
11.
Endocrinology ; 140(11): 5136-48, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10537142

RESUMEN

Long acting somatostatin-14 (SST) analogs are used clinically to inhibit tumor growth and proliferation of various tumor types via binding to specific receptors (R). We have developed a 111In-/90Y-labeled SST analog, DOTA-(D)betaNal1-lanreotide (DOTALAN), for tumor diagnosis and therapy. 111In-/90Y-DOTALAN bound with high affinity (dissociation constant, Kd, 1-12 nM) to a number of primary human tumors (n = 31) such as intestinal adenocarcinoma (n = 17; 150-4000 fmol/mg protein) or breast cancer (n = 4; 250-9000 fmol/mg protein). 111In-/90Y-DOTALAN exhibited a similar high binding affinity (Kd, 1-15 nM) for the human breast cancer cell lines T47D and ZR75-1, the prostate cancer cell lines PC3 and DU145, the colonic adenocarcinoma cell line HT29, the pancreatic adenocarcinoma cell line PANC1, and the melanoma cell line 518A2. When expressed in COS7 cells, 111In-DOTALAN bound with high affinity to hsst2 (Kd, 4.3 nM), hsst3 (Kd, 5.1 nM), hsst4 (Kd, 3.8 nM), and hsst5 (Kd, 10 nM) and with lower affinity to hsst1 (Kd, approximately 200 nM). The rank order of displacement of [125I]Tyr11-SST binding to hsst1 was: SST (IC50, 0.5 nM) >> DOTALAN (IC50, 154 nM) > lanreotide (LAN) approximate to Tyr3-octreotide (TOCT) approximate to DOTA-Tyr3-octreotide (DOTATOCT) approximate to DOTA-vapreotide (DOTAVAP; IC50, >1000 nM); that to hsst2 was: DOTATOCT approximate to TOCT approximate to DOTALAN approximate to SST approximately LAN approximate to DOTAVAP (IC50, 1.4 nM); that to hsst3 was: SST (IC50, 1.2 nM) > DOTALAN = LAN (IC50, 15 nM) approximate to TOCT (IC50, 20 nM) approximate to DOTAVAP (IC50, 28 nM) > DOTATOCT (IC50, 73 nM); that to hsst4 was: SST (IC50, 1.8 nM) approximate to DOTALAN (IC50, 2.5 nM) > LAN (IC50, 22 nM) >> DOTATOCT approximate to DOTAVAP approximate to TOCT (IC50, >500 nM); and that to hsst5 was: DOTALAN (IC50, 0.45 nM) > SST (IC50, 0.9 nM) > TOCT (IC50, 1.5 nM) > DOTAVAP (IC50, 5.4 nM) >> LAN (IC50, 21 nM) > DOTATOCT (IC50 260 nM). In Sprague Dawley rats (n = 10), 90Y-DOTALAN was rapidly cleared from the circulation and concentrated in hsst-positive tissues such as pancreas or pituitary. Taken together, our results indicate that 111In-/90Y-DOTALAN binds to a broad range of primary human tumors and tumor cell lines, probably via binding to hsst2-5. We conclude that this radiolabeled peptide can be used for hsst-mediated diagnosis (111In-DOTALAN) as well as systemic radiotherapy (90Y-DOTALAN) of human tumors.


Asunto(s)
Radioisótopos de Indio , Neoplasias/diagnóstico , Neoplasias/radioterapia , Radioisótopos de Itrio , Adenocarcinoma/metabolismo , Animales , Neoplasias de la Mama/metabolismo , Tumor Carcinoide/metabolismo , Membrana Celular/metabolismo , Neoplasias del Colon/metabolismo , Compuestos Heterocíclicos con 1 Anillo/síntesis química , Compuestos Heterocíclicos con 1 Anillo/metabolismo , Compuestos Heterocíclicos con 1 Anillo/farmacocinética , Humanos , Neoplasias Hepáticas/metabolismo , Linfoma no Hodgkin/metabolismo , Masculino , Neoplasias Pancreáticas/metabolismo , Péptidos Cíclicos/síntesis química , Péptidos Cíclicos/metabolismo , Péptidos Cíclicos/farmacocinética , Neoplasias de la Próstata/metabolismo , Ratas , Ratas Sprague-Dawley , Neoplasias de la Tiroides/metabolismo , Distribución Tisular , Células Tumorales Cultivadas
12.
Wien Klin Wochenschr ; 111(4): 161-8, 1999 Feb 26.
Artículo en Alemán | MEDLINE | ID: mdl-10192150

RESUMEN

INTRODUCTION: Intensive care physicians are frequently called upon to decide whether intensive care treatment is justified. Critically ill patients with a poor prognosis receive "Do Not Resuscitate (DNR) Orders", which entitles the physician in charge to withhold cardiopulmonary resuscitation in case of cardiac arrest. Guidelines concerning the implementation of DNR orders do not exist for Austrian intensive care units. The aim of this study was to evaluate the different practices of issuing a DNR order in the departments of intensive care medicine at the University Hospital of Innsbruck. METHODS: Forty-nine physicians working in intensive care units were interviewed about the different procedures in the management of a DNR order. Furthermore, the various answers of senior physicians and assistant physicians were evaluated. RESULTS: Thirty-nine per cent of the interviewed physicians reported that DNR orders were always issued in writing. According to the answers of 63% of intensive care physicians, the decision to issue a DNR order is usually made by senior physicians. Twenty-nine per cent mentioned that nurses are never included in the decision making process and 6%, that the family is not included in the decision making process. According to 29%, the family is regularly informed about a written DNR order. Twenty per cent of the interviewed physicians reported that the quality of the administration of a written DNR order is very good, 6% that the quality is poor. CONCLUSION: We believe that the unsatisfactory situation in regard of DNR orders is not due to inactivity on the part of physicians, but is more likely a result of the inconclusive and, in part, contradictory legal situation. The physician is compelled to take a major decision within a poorly defined legal situation.


Asunto(s)
Unidades de Cuidados Intensivos/legislación & jurisprudencia , Órdenes de Resucitación/legislación & jurisprudencia , Adulto , Actitud del Personal de Salud , Austria , Toma de Decisiones , Femenino , Hospitales Universitarios , Humanos , Tutores Legales , Masculino , Persona de Mediana Edad , Grupo de Atención al Paciente/legislación & jurisprudencia , Garantía de la Calidad de Atención de Salud/legislación & jurisprudencia
13.
Pain ; 75(2-3): 383-7, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9583774

RESUMEN

We report on two patients with morphine-related seizures associated with either intrathecal or intracerebroventricular administration. Both patients had a history of malignant tumor and both experienced the seizures following bolus application of morphine, while even higher dosages were well tolerated when continuously infused. Seizures occurred without signs of intoxication. Initiation of intrathecal morphine therapy and bolus application should be performed carefully and only when constant monitoring is provided for at least 12 h. Animal data and possible mechanisms for morphine-related seizures are discussed.


Asunto(s)
Analgésicos Opioides/administración & dosificación , Epilepsia/inducido químicamente , Morfina/administración & dosificación , Adulto , Anciano , Analgésicos Opioides/efectos adversos , Analgésicos Opioides/uso terapéutico , Carcinoma de Células Escamosas/fisiopatología , Neoplasias de Cabeza y Cuello/fisiopatología , Humanos , Inyecciones Intraventriculares , Inyecciones Espinales , Masculino , Morfina/efectos adversos , Morfina/uso terapéutico , Dolor Intratable/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/fisiopatología
14.
J Chem Neuroanat ; 13(2): 95-103, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9285354

RESUMEN

The cellular localization of binding sites for [125I]galanin was studied in explant cultures of rat neocortex, cerebellum, locus coeruleus and spinal cord by means by of autoradiography. Binding sites for the peptide were observed on a great number of astrocytes in all CNS regions studied. In addition to astrocytes, many neurones were intensely labelled by [125I]galanin. Binding of [125I]galanin (10(-8) M) to both astrocytes and neurones was markedly reduced or inhibited by the unlabelled peptide at high concentration (10(-6) M), suggesting 'specific' binding of the radioligand. Evidence for the colocalization of galanin and cholinergic receptors on astrocytes was provided by combined autoradiographic and immunohistochemical studies. Many astrocytes were labelled by [125I]galanin and immunostained with antibodies to either muscarinic or nicotinic receptors. Electrophysiological studies revealed that addition of galanin (10(-9) to 10(-7) M) to the bathing fluid caused a dose-dependent hyperpolarization of the majority of astrocytes studied. When galanin (10(-8) M) and the cholinergic agonists muscarine and nicotine (10(-6) M) were tested on the same astrocyte, all three compounds induced a hyperpolarization, suggesting a colocalization of functional galanin and cholinergic receptors on the glial membrane.


Asunto(s)
Astrocitos/química , Encéfalo/citología , Receptores Colinérgicos/análisis , Receptores de la Hormona Gastrointestinal/análisis , Médula Espinal/citología , Animales , Autorradiografía , Sitios de Unión , Células Cultivadas , Galanina/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Muscarina/farmacología , Agonistas Muscarínicos/farmacología , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Ratas , Receptores de Galanina
15.
J Neurosurg Anesthesiol ; 9(2): 141-5, 1997 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9100183

RESUMEN

Nitrous oxide (N2O) use during anesthesia for intracranial procedures has been a subject of controversy in the past. To date, the isolated influence of N2O on mean cerebral blood flow velocity in the middle cerebral artery (VMCA) has not been investigated during hypocapnia in patients with brain tumors. We compared VMCA during normocapnic (ETCO2: 40 mm Hg) and hypnocapnic (ETCO2: 25 mm Hg) inhalation of air and 50% nitrous oxide in oxygen N2O/O2 in eight patients with unilateral brain tumors on both the tumor side and the healthy side. Six patients completed the study. Mean VMCA increased during normocapnic inhalation of N2O/O2 (tumor side: 86 +/- 16 cm sec-1; healthy side: 74 +/- 17 cm sec-1) when compared with air (tumor side: 72 +/- 18 cm sec-1; healthy side: 62 +/- 14 cm sec-1, p < 0.01), whereas during hyperventilation VMCA decreased on both sides (p < 0.001). Mean VMCA values were quite similar during hypocapnic inhalation of 50% N2O/O2 (tumor side: 50 +/- 12 cm sec-1; healthy side: 45 +/- 13 cm sec-1) and air (tumor side: 51 +/- 14 cm sec-1; healthy side: 45 +/- 12 cm sec-1). The data of our study suggest that in patients with cerebral tumors the N2O-induced increase in mean VMCA can be completely reversed by hyperventilation.


Asunto(s)
Anestésicos por Inhalación , Neoplasias Encefálicas/cirugía , Dióxido de Carbono/sangre , Arterias Cerebrales/fisiopatología , Óxido Nitroso , Adulto , Anestesia por Inhalación , Velocidad del Flujo Sanguíneo , Circulación Cerebrovascular , Femenino , Lateralidad Funcional , Humanos , Masculino , Persona de Mediana Edad
16.
Wien Klin Wochenschr ; 108(1): 5-8, 1996.
Artículo en Alemán | MEDLINE | ID: mdl-8677660

RESUMEN

The treatment of intractable pain, especially in cancer patients, often sets problems to patient and therapist. While epidural and intrathecal spinal administration of opiates is a routine treatment in pain with a sub-diaphragmatic topography it is almost ineffective in cervicocephalic or thoracic cancer. An alternative here is the administration of morphine into the lateral or third ventricle by a catheter-reservoir system. We report on our experience in the treatment of twenty patients, mostly suffering from cancer (18 cases), from 1990 to 1993. It is shown to be an effective, non-destructive method with minimal side effects in the treatment of nociceptive pain. Analgesia takes effect within a few minutes and the necessary doses are low. Our results agree with those of other authors describing good to excellent results in 95% of patients with somatogenic pain. However, no or only minimal effect is achieved in the treatment of neurogenic pain by intracerebroventricular morphine therapy.


Asunto(s)
Encéfalo/efectos de los fármacos , Catéteres de Permanencia , Morfina/administración & dosificación , Neoplasias/fisiopatología , Dolor Intratable/tratamiento farmacológico , Ventriculostomía/instrumentación , Femenino , Humanos , Bombas de Infusión , Masculino , Dimensión del Dolor , Técnicas Estereotáxicas/instrumentación
17.
Hum Genet ; 95(5): 507-12, 1995 May.
Artículo en Inglés | MEDLINE | ID: mdl-7759070

RESUMEN

A well defined polymorphism of vitamin D-binding/group-specific component (GC) residues in exon 11. To characterize the molecular basis of GC*1A2 and GC*1A3, common in some Asian populations, we analyzed all coding exons amplified by the polymerase chain reaction. GC*1F was divided into GC*1FC and GC*1FT by a C-T transition in the third nucleotide of the codon (TGC/T) for cysteine283 in exon 8. The sequencing of exons 8 and 11 showed that GC*1A2 and GC*1A3 had occurred on a GC*1FC genetic background. They also shared a substitution of cysteine (TGC) for arginine (CGC) at position 429 in exon 11. GC*1A2 was characterized by having glycine (GGC) instead of serine (AGC) at position 335 in exon 9. GC*1A2 evolved from GC*1FT by three mutational events, i.e. GC*1FT-->GC*1FC-->GC*1A3-->GC*1A2. No evidence was obtained for the existence of the duplicated gene GC*1F.1A2 suggested by isoelectric focusing (IEF) of serum samples. The idea that the characteristic banding pattern of GC*1F.1A2 after IEF results from partial formation of a disulfide bond in the additional cysteine at position 429 is discussed.


Asunto(s)
Alelos , Evolución Biológica , Mutación , Proteína de Unión a Vitamina D/genética , Secuencia de Bases , ADN/análisis , ADN/química , Cartilla de ADN/química , Exones , Femenino , Humanos , Japón , Masculino , Biología Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo Conformacional Retorcido-Simple
18.
Jpn J Hum Genet ; 40(1): 149-51, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7780166

RESUMEN

A novel sequence polymorphism due to a T to C transition at the third nucleotide of the codon for Cys283 of the vitamin D-binding protein (GC) gene assigned to chromosome 4q13-4q21.1 was revealed by sequence analysis. Population studies by single strand conformation polymorphism (SSCP) analysis showed this GC-283.3 site was polymorphic in a Black African population but monomorphic in a European population.


Asunto(s)
Población Negra/genética , Exones , Polimorfismo Genético , Proteína de Unión a Vitamina D/genética , Secuencia de Bases , Cromosomas Humanos Par 4 , Frecuencia de los Genes , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa
19.
Vox Sang ; 68(1): 50-4, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7725672

RESUMEN

The structure and organization of the human vitamin-D-binding protein gene (DBP, group-specific component, GC) have recently been determined. Each exon may now be amplified by the PCR method using oligonucleotide primers deduced from the intron sequences near their 5' ends and 3' ends. In this study we examined the anodal GC variants 1A1 and 2A9. Genomic DNA of the variant 1A1 was obtained from Australian Aborigines and from South African Bantu-speaking Blacks. Amplification and sequencing of exon 11 of 1A1 revealed a point mutation in codon 429 at the second position. It is remarkable that this mutation was found in the Australian 1A1 variant and in the African 1A1 variant, and raises the question whether the mutation in these two ethnic groups has a common origin. Genomic DNA of the 2A variant called 2A9 was obtained from South Germany and a point mutation also concerning position 429 in exon 11 was found. The nucleotide exchange in this case, however, was at the first position of the codon. The widely distributed genetic polymorphism of DBP/GC is located in exon 11 and is characterized by substitution at amino acid positions 416 and 420. Variant 1A1 is due to a second site mutation of the allele GC*1F; variant 2A9 is due to a mutation in the GC*2 allele.


Asunto(s)
Población Negra/genética , Nativos de Hawái y Otras Islas del Pacífico/genética , Proteína de Unión a Vitamina D/genética , Australia , Secuencia de Bases , Variación Genética , Alemania , Humanos , Datos de Secuencia Molecular , Mutación , Sudáfrica/etnología
20.
Funct Neurol ; 9(1): 29-34, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-8082851

RESUMEN

Intrathecal application of baclofen is considered the treatment of choice in patients suffering from spinal spasticity insufficiently responding to conventional oral antispastic medication. This approach has also been used successfully in cases with spasticity of supraspinal origin. To achieve a good therapeutic response in the latter condition the amount of intrathecal baclofen has to be approximately twice the dosage required in spinal spasticity. We report on 8 patients suffering from supraspinal spasticity due to severe traumatic brain injury. Intrathecal baclofen reduced spasticity in all patients (mean Ashworth Score from 3.9 to 1.6; mean Reflex Score from 4.0 to 1.4). In some cases improvement of motor performance and in one case recovery of bladder function were noted. In two patients focal epileptic seizures with secondary generalization seemed to be associated with the application of baclofen. The local intrathecal application of baclofen has proven to be an effective therapy in otherwise intractable cases of severe supraspinal spasticity.


Asunto(s)
Baclofeno/uso terapéutico , Lesiones Encefálicas/complicaciones , Inyecciones Espinales , Espasticidad Muscular/etiología , Músculos/fisiopatología , Enfermedades de la Columna Vertebral/tratamiento farmacológico , Enfermedades de la Columna Vertebral/etiología , Enfermedad Aguda , Adulto , Baclofeno/administración & dosificación , Humanos , Masculino , Índice de Severidad de la Enfermedad , Enfermedades de la Columna Vertebral/fisiopatología , Resultado del Tratamiento
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