Optical communications downlink from a low-earth orbiting 1.5U CubeSat.

In this article, we present the first demonstration of an optical communications downlink from a low-earth orbiting free-flying CubeSat. Two 1.5U vehicles, AC7-B&C, built under NASA's Optical Communications and Sensors Demonstration (OCSD) program were launched in November 2017 and subsequently placed into a 450-km, 51.6° inc. circular orbit. Pseudorandom data streams using on-off key (OOK) modulation were transmitted from AC-7B to a 40 cm aperture telescope located at sea level in El Segundo, CA. At 200 Mbps, without forward error correction (FEC), we achieved a 115-second link that was ~78% error free, with the remaining portion exhibiting an error rate below 1E-5. At the time of the engagement, the 1064-nm laser transmitter was operating at 2 W (half capacity) with a full width half maximum (FWHM) beam divergence of ~1 mrad, which was approximately double the anticipated pointing accuracy of the vehicle.

Helicobacter pylori vacA and cagA genotype diversity and interferon gamma expression in patients with chronic gastritis and patients with gastric cancer.

BACKGROUND: Helicobacter pylori (H. pylori) is the main risk factor for the development of chronic gastritis, gastric ulcer, and gastric cancer. In H. pylori-infected individuals, the clinical result is dependent on various factors, among which are bacterial components, the immune response, and environmental influence. AIMS: To compare IFN-γ expression with the H. pylori vacA and cagA genotypes in patients with chronic gastritis and patients with gastric cancer. METHODS: Ninety-five patients diagnosed with chronic gastritis and 20 with gastric cancer were included in the study. Three gastric biopsies were taken; one was used for the molecular detection and genotyping of H. pylori; another was fixed in absolute alcohol and histologic sections were made for determining IFN-γ expression through immunohistochemistry. RESULTS: No differences were found in the cells that expressed IFN-γ between the patients with chronic gastritis (median percentage of positive cells: 82.6% in patients without H. pylori and 82% in infected persons) and those with gastric cancer (70.5% in H. pylori-negative patients and 78.5% in infected persons). IFN-γ expression was 69% in chronic gastritis patients infected with H. pylori vacAs2m2/cagA⁻ it was 86.5% in patients infected with H. pylori vacAs1m2/cagA⁻, 86.5% in vacAs1m1/cagA⁻, and 82% in vacAs1m1/cagA⁺. Similar data were found in the patients with gastric cancer. CONCLUSIONS: IFN-γ expression varied depending on the H. pylori vacA and cagA genotype, but not in accordance with the presence of chronic gastritis or gastric cancer.

10-MV SBRT FFF IRRADIATION TECHNIQUE IS ASSOCIATED TO THE LOWEST PERIPHERAL DOSE: THE OUTCOME OF 142 TREATMENT PLANS FOR THE 10 MOST COMMON TUMOUR LOCATIONS.

There is a growing interest in the combined use of Stereotactic Body Radiation Therapy (SBRT) with Flattening Filter Free (FFF) due to the high local control rates and reduced treatment times, compared to conventionally fractionated treatments. It has been suggested that they may also provide a better radiation protection to radiotherapy patients as a consequence of the expected decrease in peripheral doses. This work aims to determine this reduction in unattended out-of-field regions, where no CT information is available but an important percentage of second primary cancers occur. For that purpose, ten different cases suitable for SBRT were chosen. Thus, 142 different treatment plans including SBRT, as well as 3D-CRT, IMRT and VMAT (with standard fractionation) in low and high energies for Varian (FF and FFF), Siemens and Elekta machines were created. Then, photon and neutron peripheral dose in 14 organs were assessed and compared using two analytical models. For the prostate case, uncomplicated and cancer free control probability estimation was also carried out. As a general behavior, SBRT plans led to the lowest peripheral doses followed by 3D-CRT, VMAT and IMRT, in this order. Unflattened beams proved to be the most effective in reducing peripheral doses, especially for 10 MV. The obtained results suggest that FFF beams for SBRT with 10 MV represent the best compromise between dose delivery efficiency and peripheral dose reduction.

The 1997 Mars Pathfinder Spacecraft Landing Site: Spillover Deposits from an Early Mars Inland Sea.

The Martian outflow channels comprise some of the largest known channels in the Solar System. Remote-sensing investigations indicate that cataclysmic floods likely excavated the channels ~3.4 Ga. Previous studies show that, in the southern circum-Chryse region, their flooding pathways include hundreds of kilometers of channel floors with upward gradients. However, the impact of the reversed channel-floor topography on the cataclysmic floods remains uncertain. Here, we show that these channel floors occur within a vast basin, which separates the downstream reaches of numerous outflow channels from the northern plains. Consequently, floods propagating through these channels must have ponded, producing an inland sea, before reaching the northern plains as enormous spillover discharges. The resulting paleohydrological reconstruction reinterprets the 1997 Pathfinder landing site as part of a marine spillway, which connected the inland sea to a hypothesized northern plains ocean. Our flood simulation shows that the presence of the sea would have permitted the propagation of low-depth floods beyond the areas of reversed channel-floor topography. These results explain the formation at the landing site of possible fluvial features indicative of flow depths at least an order of magnitude lower than those apparent from the analyses of orbital remote-sensing observations.

Characterization of radon levels in soil and groundwater in the North Maladeta Fault area (Central Pyrenees) and their effects on indoor radon concentration in a thermal spa.

Radon levels in the soil and groundwater in the North Maladeta Fault area (located in the Aran Valley sector, Central Pyrenees) are analysed from both geological and radiation protection perspectives. This area is characterized by the presence of two important normal faults: the North Maladeta fault (NMF) and the Tredós Fault (TF). Two primary aspects make this study interesting: (i) the NMF shows geomorphic evidence of neotectonic activity and (ii) the presence of a thermal spa, Banhs de Tredós, which exploits one of the several natural springs of the area and needs to be evaluated for radiation dosing from radon according to the European regulation on basic safety standards for protection against ionizing radiation. The average soil radon and thoron concentrations along a profile perpendicular to the two normal faults - 22 ±â€¯3 kBq·m-3 and 34 ±â€¯3 kBq·m-3, respectively - are not high and can be compared to the radionuclide content of the granitic rocks of the area, 25 ±â€¯4 Bq·kg-1 for 226Ra and 38 ±â€¯2 Bq·kg-1 for 224Ra. However, the hypothesis that the normal faults are still active is supported by the presence of anomalies in both the soil radon and thoron levels that are unlikely to be of local origin together with the presence of similar anomalies in CO2 fluxes and the fact that the highest groundwater radon values are located close to the normal faults. Additionally, groundwater 222Rn data have complemented the hydrochemistry data, enabling researchers to better distinguish between water pathways in the granitic and non-granitic aquifers. Indoor radon levels in the spa vary within a wide range, [7-1664] Bq·m-3 because the groundwater used in the treatment rooms is the primary source of radon in the air. Tap water radon levels inside the spa present an average value of 50 ±â€¯8 kBq·m-3, which does not exceed the level stipulated by the Spanish Nuclear Safety Council (CSN) of 100 kBq·m-3 for water used for human consumption. This finding implies that even relatively low radon concentration values in water can constitute a relevant indoor radon source when the transfer from water to indoor air is efficient. The estimated effective dose range of values for a spa worker due to radon inhalation is [1-9] mSv·y-1. The use of annual averaged radon concentration values may significantly underestimate the dose in these situations; therefore, a detailed dynamic study must be performed by considering the time that the workers spend in the spa.

[Clinical features of familial Creutzfeldt-Jakob disease and the E200K mutation in Spain]. / Características clínicas de la enfermedad de Creutzfeldt-Jakob familiar y mutación E200K en España.

INTRODUCTION: Creutzfeldt-Jakob disease (CJD) is an infrequent pathology affecting the central nervous system (about 1/1,000000) that has a subacute progression and, for the time being, a fatal prognosis. The familial forms account for between 5-10% of cases and one of the most frequent is that produced by the E200K mutation of prion protein gene (PRNP), which has not been reported in Spanish families although Spain is considered to be part of the expansion circuit of the mutation. CASE REPORTS: We report on a Spanish family with three cases of CJD. The disease affected three females (our patient and two paternal aunts), who started with dementia, myoclonias, gait disorders and cortical blindness at the ages of 61, 53 and 55 years. Progress in all three cases was torpid and the symptoms advanced in a short time. Results of the complementary tests that were carried out were normal, except for the electroencephalogram, which was compatible with CJD in all three cases, and the imaging tests, which revealed cortical-subcortical atrophy. A confirmatory diagnosis was reached from a biopsy, the clinical picture and the family history in the cases of the paternal aunts and from a genetic study of our patient, which confirmed the E200K mutation. CONCLUSIONS: This family confirms the presence of familial forms of CJD in Spain, more specifically the E200K mutation, and highlights the role of Spain in the possible transmission of this mutation.

Correction: 3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

[This corrects the article DOI: 10.1371/journal.pone.0166767.].

Soil radon dynamics in the Amer fault zone: An example of very high seasonal variations.

Soil radon levels of the Amer fault zone have been measured for a 4 year-period with the aim of checking seasonal fluctuations obtained in previous studies and to understand radon origin and dynamics. In this manuscript additional results are presented: updated continuous and integrated soil radon measurements, radionuclide content of soil materials and a detailed analysis of an urban profile by means of the electrical resistivity imaging technique and punctual soil radon, thoron and CO2 measurements. Integrated and continuous measurements present a wide range of values, [0.2-151.6] kBq m(-3) for radon, [4.5-39.6] kBq m(-3) for thoron and [4.0-71.2] g m(-2) day(-1) for CO2. The highest soil radon levels in the vicinity of the Amer fault (>40 kBq m(-3)) are found close to the fractured areas and present very important fluctuations repeated every year, with values in summer much higher than in winter, confirming previous studies. The highest radon values, up to 150 kBq m(-3), do not have a local origin because the mean value of radium concentration in this soil (19 ± 5 Bq kg(-1)) could not explain these values. Then soil radon migration through the fractures, influenced by atmospheric parameters, is assumed to account for such a high seasonal fluctuation. As main conclusion, in fractured areas, seasonal variations of soil radon concentration can be very important even in places where average soil radon concentration and radium content are not especially high. In these cases the migration capability of the soil is given not by intrinsic permeability but by the fracture structure. Potential risk estimation based on soil radon concentration and intrinsic permeability must be complemented with geological information in fractured systems.

Life cycle cost of a hybrid forward osmosis - low pressure reverse osmosis system for seawater desalination and wastewater recovery.

In recent years, forward osmosis (FO) hybrid membrane systems have been investigated as an alternative to conventional high-pressure membrane processes (i.e. reverse osmosis (RO)) for seawater desalination and wastewater treatment and recovery. Nevertheless, their economic advantage in comparison to conventional processes for seawater desalination and municipal wastewater treatment has not been clearly addressed. This work presents a detailed economic analysis on capital and operational expenses (CAPEX and OPEX) for: i) a hybrid forward osmosis - low-pressure reverse osmosis (FO-LPRO) process, ii) a conventional seawater reverse osmosis (SWRO) desalination process, and iii) a membrane bioreactor - reverse osmosis - advanced oxidation process (MBR-RO-AOP) for wastewater treatment and reuse. The most important variables affecting economic feasibility are obtained through a sensitivity analysis of a hybrid FO-LPRO system. The main parameters taken into account for the life cycle costs are the water quality characteristics (similar feed water and similar water produced), production capacity of 100,000 m(3) d(-1) of potable water, energy consumption, materials, maintenance, operation, RO and FO module costs, and chemicals. Compared to SWRO, the FO-LPRO systems have a 21% higher CAPEX and a 56% lower OPEX due to savings in energy consumption and fouling control. In terms of the total water cost per cubic meter of water produced, the hybrid FO-LPRO desalination system has a 16% cost reduction compared to the benchmark for desalination, mainly SWRO. Compared to the MBR-RO-AOP, the FO-LPRO systems have a 7% lower CAPEX and 9% higher OPEX, resulting in no significant cost reduction per m(3) produced by FO-LPRO. Hybrid FO-LPRO membrane systems are shown to have an economic advantage compared to current available technology for desalination, and comparable costs with a wastewater treatment and recovery system. Based on development on FO membrane modules, packing density, and water permeability, the total water cost could be further reduced.

Leiomiosarcoma primario de hueso en fémur distal metastásico a clavícula: reporte de un caso / Primary leiomyosarcoma of bone in the distal femur with clavicle metastasis: a case report

El leiomiosarcoma (LMS) es un tipo de tumor de células fusiformes de muy baja incidencia, que tiene un comportamiento agresivo, con alta tasa de mortalidad, por lo que el manejo debe ser quirúrgico, con una resección amplia de la lesión. No está claro el papel de la radio ni de la quimioterapia en su manejo. Presentamos a una paciente de 28 años que consultó por dolor de 2 meses en la rodilla derecha. Radiográficamente, se caracterizó como una lesión osteolítica pura en el fémur distal. La resonancia nuclear magnética (RNM) contrastada mostró áreas hipervasculares dentro del tumor. La gammagrafía mostró un marcado aumento en la captación de radiotrazadores. Se tomó una biopsia, con un informe de patología de LMS óseo bien diferenciado. Se trató con 3 ciclos de quimioterapia neoadyuvante preoperatoria con ifosfamida 1.000 mg/m2 en los días 1 a 3, además de doxorrubicina 70 mg/m2 , y resección quirúrgica de la lesión y salvamento de la extremidad con endoprótesis de rodilla. Una vez que se resecó la lesión, la paciente recibió quimioterapia adyuvante con 4 ciclos de gencitabina 1.000 mg/m2 entre los días 1 y 8, y doxetacel 70 mg/m2 el día 1. Durante los dos meses de seguimiento, la paciente presenóa una fractura en el tercio medio de la clavícula, compatible con una lesión patológica en radiografías y tomografía por emisión de positrones (TEP). La biopsia reveló una lesión metastásica de LMS óseo que fue tratada mediante resección quirúrgica de la clavícula. Este es un caso único, dado que, durante el seguimiento, recibió tratamiento adyuvante con quimioterapia y se evaluó con una TEP, con una evolución clínica satisfactoria y sin evidencia de nuevas lesiones

Leiomyosarcoma (LMS) is a type of spindle-cell tumor of very low incidence that tumor has an aggressive behavior, with high mortality rates; therefore, its management must be surgical, with a wide resection of the lesion. The role of radio and chemotherapy in its management is not clear. We present the case of a 28-year-old female patient who consulted for pain lasting 2 months in the right knee. Radiographically, it was characterized as a pure osteolytic lesion in the distal femur. Contrast magnetic resonance imaging (MRI) showed hypervascular areas within the tumor. The scintigraphy showed a marked increase in radiotracer uptake. A biopsy was taken, with a pathology report of well-differentiated osseous LMS. It was treated with 3 cycles of preoperative neoadjuvant chemotherapy with ifosfamide 1,000 mg/m2 in the first 3 days, as well as doxorubicin 70 mg/m2 , and surgical resection of the lesion and limb salvage with knee endoprosthesis. Once the lesion was resected, the patient underwent adjuvant chemotherapy, with 4 cycles of gencitabine 1,000 mg/m2 between days 1 and 8, and doxetacel 70 mg/m2 on day 1. During the 2-month follow-up, the patient presented a fracture in the middle third of the clavicle, which was compatible with a pathological lesion on radiographs and positron-emission tomography (PET) scans. The biopsy showed a metastatic lesion of bone LMS, which was treated by surgical resection of the clavicle. This is a unique case, given that, during the follow-up, the patient underwent adjuvant treatment with chemotherapy, and was evaluated with a PET scan, with a satisfactory clinical evolution and no evidence of new lesions.

Tumor fibroblástico inguinal superficial positivo para CD34: reporte de un caso y revisión de la literatura / Inguinal superficial cd34-positive fibroblastic tumor: case report and literature review

El tumor fibroblástico superficial de tejidos blandos positivo para antígeno CD34 (CD34) es un tumor raro, de baja frecuencia, que se caracteriza histológicamente por un marcado pleomorfismo, baja actividad mitótica, e inmunoreactividad difusa para CD34. Puede tener un comportamiento similar al de un tumor mesenquimal de malignidad intermedia. Existen sólo 52 casos publicados en la literatura. Se presenta el caso de una paciente de 31 años con una masa en tejidos blandos en región inguinal izquierda, de crecimiento progresivo, de varios meses de evolución dolorosa. La masa fue biopsiada y, con la sospecha de un tumor fibroblástico superficial positivo para CD34, fue posteriormente tratada con una resección ampliada de la lesión y con cobertura del defecto en la piel con un colgajo local de avance de V-Y, con una evolución satisfactoria en su seguimiento postquirúrgico. El reporte de patología confirmó la sospecha diagnóstica de un tumor con reactividad fuerte para CD34, con proteína P53 en 60% a 70%, antígeno Ki67 menor al 15%, sin pérdida de proteína nuclear INI-1, y negatividad para CD31, CD163, AE1AE3, CAM5.2, EMA, CD30, receptores de progestágenos, proteína S100, y desmina, con bordes negativos.

Superficial CD34 (CD34) antigen positive fibroblastic soft-tissue tumor is a rare, lowfrequency tumor, characterized histologically by marked pleomorphism, low mitotic activity, and diffuse immunoreactivity for CD34. It may behave like a mesenchymal tumor of intermediate malignancy. There are only 52 cases published in the literature. We present the case of a 31-year-old patient with a long progressive and painful growth of a soft-tissue lesion in the left inguinal region. The mass was biopsied and, with the suspicion of a superficial CD34-positive fibroblast tumor, it was subsequently treated with an enlarged resection of the lesion and covering the skin defect with a local V-Y advancement flap, with a satisfactory evolution in the postoperative follow-up. The pathology report confirmed the diagnostic suspicion of a tumor with strong reactivity for CD34, with P53 protein in 60% to 70%, Ki67 antigen in less than 15%, without loss of INI-1, and with negativity for CD31, CD163, AE1AE3, CAM5.2, EMA, CD30, progestin receptors, S100 protein and desmin, with negative borders.

3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measurements (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discretization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.

A simple flow cytometry method improves the detection of phosphatidylserine-exposing extracellular vesicles.

BACKGROUND: Plasma contains cell-derived extracellular vesicles (EVs), which participate in physiopathological processes and have potential applications as disease biomarker. However, the enumeration of EVs faces major problems, due to their sub-micrometer size and to intrinsic limitations in methods of characterization, mainly flow cytometry (FCM). OBJECTIVES: Our objective is to enumerate EVs in plasma, by taking as the prototype the population of phosphatidylserine (PS)-exposing EVs, which constitute one of the major EV populations and are responsible for thrombotic disorders. METHODS: The concentration of PS-exposing EVs in platelet-free plasma (PFP) of healthy subjects was measured by FCM using either light scattering or fluorescence as the trigger and fluorescent Annexin-5 (Anx5) as the specific label. In addition, PS-exposing EVs were enumerated by electron microscopy (EM) after labeling with Anx5 gold nanoparticles and sedimentation on EM grids. RESULTS: We show that about 50× more Anx5-positive EVs are detected by FCM when detection is triggered on fluorescence as compared with light scattering. By fluorescence triggering, concentrations of 22 000-30 000 Anx5-positive EVs per µL PFP were determined, using two different flow cytometers. The limit of detection of the fluorescence triggering method was estimated at about 1000-2500 Anx5 molecules. Results from EM suggest that EVs down to 100-150 nm diameter are detected by fluorescence triggering. CONCLUSION: This study presents a simple method for enumerating EVs. We believe that this method is applicable in a general context and will improve our understanding of the roles of EVs in pathophysiological situations, which will open avenues for the development of EV-based diagnosis assays.

Signatures of the Giant Pairing Vibration in the 14C and 15C atomic nuclei.

Giant resonances are collective excitation modes for many-body systems of fermions governed by a mean field, such as the atomic nuclei. The microscopic origin of such modes is the coherence among elementary particle-hole excitations, where a particle is promoted from an occupied state below the Fermi level (hole) to an empty one above the Fermi level (particle). The same coherence is also predicted for the particle-particle and the hole-hole excitations, because of the basic quantum symmetry between particles and holes. In nuclear physics, the giant modes have been widely reported for the particle-hole sector but, despite several attempts, there is no precedent in the particle-particle and hole-hole ones, thus making questionable the aforementioned symmetry assumption. Here we provide experimental indications of the Giant Pairing Vibration, which is the leading particle-particle giant mode. An immediate implication of it is the validation of the particle-hole symmetry.

Recent advances in magnetic resonance imaging of the musculoskeletal system.

Numerous recent technical innovations in magnetic resonance imaging have dramatically improved the imaging evaluation of musculoskeletal disease; however, with the introduction of new techniques comes the risk of inappropriate applications and unanticipated pitfalls in interpretation. Some of the practical and theoretical implications of these recent innovations as well as potential caveats associated with their use are highlighted in the following discussion.

Clinical trial of remote radiologist services for a military installation.

It is often difficult to provide continuity of professional radiological services at U.S. military facilities located at a distance from major metropolitan areas. To address this problem, we have designed and evaluated a program to send x-ray films from a U.S. Army hospital to a remote site for expert radiological interpretation. Nine hundred and forty-two x-ray studies were sent by U.S. Express Mail from the Radiology Department of a U.S. Army Hospital over a 2-month period. The typed reports were sent back to the hospital through the use of a computer-to-computer telephone link within 72 hours of film transport. No studies were lost and security of all studies was maintained. This program offers a cost-effective, otherwise unavailable means to provide high quality professional radiological services to U.S. military facilities both inside the United States and in foreign countries.

[A radiological study of the cervical alterations in Down syndrome. New findings on computerized tomography and three dimensional reconstructions]. / Estudio radiológico de las alteraciones cervicales en el síndrome de Down. Nuevos hallazgos mediante tomografía computarizada y reconstrucciones tridimensionales.

OBJECTIVE: We studied a large proportion of the population in our health district who have Down's syndrome to determine the incidence and variety of changes in the spine and to define the guidelines for preventive diagnosis advisable in relation to atlanto-axial instability, a common disorder in these patients. PATIENTS AND METHODS: First phase: a plain X-ray of the cervical spine in a neutral lateral projection and in flexion in 188 patients, measuring the atlanto-odontoid distance. Second phase: computerized tomography (CT) studies and three dimensional reconstructions in 25 patients (13.3%) chosen at random. The axial cuts from the upper portion of C3 to the occiput were 3 mm in thickness with 3 mm intervals and a standard reconstruction algorithm. RESULTS: The incidences of atlanto-axial instability with an atlodontoid distance (3)5 mm were not comparable with the published series. There was a lower incidence (4.2%), with no difference between measurements in flexion and in the neutral lateral views. There was a greater incidence of malformations than in other reports, including a rare case of os odontoideum and also constant asymmetry of the occipital condyles (100%) in the patients of the CT series and consequently instability of the atlas (96%) and off-centered odontoides (84%). CONCLUSIONS: The study showed that there was deficient asymmetrical development of the occipital bone, which caused different heights of the occipital condyles and led to cervico-cranial mal-position. For study of the degree of error of position and congenital anomalies. We recommend replacing plain X-ray studies by CT with three dimensional reconstructions.

[The pyramidal tract: new pathways]. / La vía piramidal: nuevas trayectorias.

OBJECTIVE: To review some anatomofunctional aspects of the pyramidal tract which are relevant in clinical practice, especially the newer concepts. DEVELOPMENT: a) Although the motor function is best known, the pyramidal tract also has sensory functions, modulating the transmission of impulses in the spinal cord. In fact, motor function is a recent acquisition on the evolutionary scale. b) Other descending pathways, such as the cortico reticulospinal path, participate in voluntary movements. However, the pyramidal pathway is necessary for fine movements of the hand. c) Most of the pyramidal fibres control movements of the contralateral side of the body, but there are a few fibres which do not cross to the other side and play a part in ipsilateral body movements. These fibres seem to contribute to motor recovery following a brain lesion. d) Classically it is recognized that the motor cortex and pyramidal fibres follow a somatotopical distribution. Nevertheless territories corresponding to different parts of the body are superimposed to a considerable extent and may be modified on very diverse occasions. e) Experimentally it has been proved that a circumscribed lesion of the pyramidal pathway does not cause hyper reflexia or spasticity. The hyper reflexia and spasticity habitually seen in patients with pyramidal syndrome is due to lesions of other descending pathways. CONCLUSION: The pyramidal tract is anatomically and functionally related to other nerve structures and its activity is therefore integrated within the nervous system.

[Deferred repair of surgical ureteral lesions]. / Reparación diferida de las lesiones ureterales quirúrgicas.

Our experience in surgical injuries of the ureter, as well as the therapeutic approach followed to repair them as expounded in this paper. Immediate nephrostomy following diagnosis, and restoration deferred a minimum of three weeks have provided good results, as well as it has allowed us to detect and achieve spontaneous restoration in one case. These reasons, together with the absence of technical difficulties during the second intervention, invite us to consider the reevaluation and deferred restoration--if appropriate--of the surgical ureteral injuries as a therapeutic approach from which a number of patients can profit.