RESUMEN
Crohn's disease is a chronic inflammatory disease which may involve any segment of the gastrointestinal tract, most frequently the terminal ileum, the large intestine, and the perianal region. The symptoms of perianal Crohn's disease include skin disorders, hemorrhoids, anal ulcers, anorectal stenosis, perianal abscesses and fistulas, rectovaginal fistulas and carcinoma of the perianal region. The perianal manifestations of Crohn's disease cause great discomfort to the patient and are among the most difficult aspects to treat. Management of perianal disease requires a combination of different imaging modalities and a close cooperation between gastroenterologists and dedicated surgeons.
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AIM: This randomized double blind controlled study is aimed at determining the effect of repeated vibratory stimuli focally applied to the contracted quadriceps muscles (repeated muscle vibration=rMV) on bone mineral density, leg power and balance of postmenopausal osteoporotic women. METHODS: The study has been conducted on 40 voluntary postmenopausal osteoporotic women, randomised at 2 groups for rMV treatment and for control. The treatment group underwent rMV (100Hz, 300-500 µm; three applications per day, each lasting 10-minutes, for 3 consecutive days) applied to voluntary contracted quadriceps (VC=vibrated and contracted group). The control group, received a sham stimulation on contracted quadriceps (NV=non vibrated group). Bone mineral density T-score of proximal femur of the participants, was evaluated in two weeks before and 360 days after intervention; body balance and explosive leg power were measured 1 day before, 30 days and 360 days after treatment. RESULTS: VC group T-score at one year didn't change significantly relative to baseline values (pretreatment: -2.61±0.11, post-treatment -2.62±0.13); conversely in NV subjects T-score decreased significantly from -2.64 ± 0.15 SD down to -2.99 ± 0.28 SD. A significant improvement of balance and explosive leg power was observed only in VC group at 30 and 360 days after the intervention. CONCLUSION: We conclude that rMV is a safe, short-lasting and non-invasive treatment that can significantly and persistently improve muscle performance and can effectively counteract progressive demineralisation in postmenopausal and osteoporotic women.
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Extremidad Inferior/fisiología , Fuerza Muscular/fisiología , Osteoporosis Posmenopáusica/terapia , Equilibrio Postural/fisiología , Vibración/uso terapéutico , Anciano , Método Doble Ciego , Femenino , Humanos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/fisiopatologíaRESUMEN
Self-motion perception and the vestibulo-ocular reflex (VOR) were investigated in healthy subjects during asymmetric whole body yaw plane oscillations while standing on a platform in the dark. Platform oscillation consisted of two half-sinusoidal cycles of the same amplitude (40°) but different duration, featuring a fast (FHC) and a slow half-cycle (SHC). Rotation consisted of four or 20 consecutive cycles to probe adaptation further with the longer duration protocol. Self-motion perception was estimated by subjects tracking with a pointer the remembered position of an earth-fixed visual target. VOR was measured by electro-oculography. The asymmetric stimulation pattern consistently induced a progressive increase of asymmetry in motion perception, whereby the gain of the tracking response gradually increased during FHCs and decreased during SHCs. The effect was observed already during the first few cycles and further increased during 20 cycles, leading to a totally distorted location of the initial straight-ahead. In contrast, after some initial interindividual variability, the gain of the slow phase VOR became symmetric, decreasing for FHCs and increasing for SHCs. These oppositely directed adaptive effects in motion perception and VOR persisted for nearly an hour. Control conditions using prolonged but symmetrical stimuli produced no adaptive effects on either motion perception or VOR. These findings show that prolonged asymmetric activation of the vestibular system leads to opposite patterns of adaptation of self-motion perception and VOR. The results provide strong evidence that semicircular canal inputs are processed centrally by independent mechanisms for perception of body motion and eye movement control. These divergent adaptation mechanisms enhance awareness of movement toward the faster body rotation, while improving the eye stabilizing properties of the VOR.
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Percepción de Movimiento/fisiología , Reflejo Vestibuloocular/fisiología , Adulto , Movimientos Oculares/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Rotación , Adulto JovenRESUMEN
AIM: This double-blind randomized controlled study aims at determining the effect of repeated muscle vibration (rMV) on explosive and reactive leg power and on knee laxity of female volleyball players. METHODS: Eighteen voluntary volleyball athletes, belonging to the same senior regional level team (age=22.7 ± 3 years, height=180.3 ± 5 cm, mass= 64 ± 4 kg) were assigned to three groups (N.=6) for vibration on contracted quadriceps (VC), vibration on relaxed muscle (VR), and sham vibration (NV), respectively. Intervention consisted in 3 rMV sessions performed in 3 consecutive days. In each session, 100 Hz, 300-500 µm amplitude vibratory stimuli were bilaterally delivered to the quadriceps in three consecutive 10-minutes applications. Explosive and reactive leg power and knee joint laxity were evaluated 1 day before, and 1, 30, and 240 days after intervention. RESULTS: In VC group, explosive and reactive leg power increased respectively by ~16% and ~9% at 1 day, by ~19% and ~11% at 30 days and by ~26% and ~13% at 240 days, concomitantly knee laxity decreased by ~6%, ~15% and ~18% at the same times. These changes were significantly larger than in the other groups, in which leg power increment and knee joint laxity reduction remained close to ~3%, ~5% and ~10% at 1, 30 and 240 days, respectively. CONCLUSION: Combined bilateral voluntary contraction and rMV of the quadriceps muscles is a short-lasting, non-invasive technique that can significantly and persistently improve muscle performance and knee laxity in volleyball women players.
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Inestabilidad de la Articulación/prevención & control , Articulación de la Rodilla/fisiopatología , Pierna/fisiología , Modalidades de Fisioterapia , Músculo Cuádriceps/fisiología , Voleibol/fisiología , Método Doble Ciego , Femenino , Estudios de Seguimiento , Humanos , Inestabilidad de la Articulación/fisiopatología , Vibración , Adulto JovenRESUMEN
Orientation and movement relies on both visual and vestibular information mapped in separate coordinate systems. Here, we examine how coordinate systems interact to guide eye movements of rabbits. We exposed rabbits to continuous horizontal optokinetic stimulation (HOKS) at 5°/s to evoke horizontal eye movements, while they were statically or dynamically roll-tilted about the longitudinal axis. During monocular or binocular HOKS, when the rabbit was roll-tilted 30° onto the side of the eye stimulated in the posterior â anterior (P â A) direction, slow phase eye velocity (SPEV) increased by 3.5-5°/s. When the rabbit was roll-tilted 30° onto the side of the eye stimulated in the A â P direction, SPEV decreased to ~2.5°/s. We also tested the effect of roll-tilt after prolonged optokinetic stimulation had induced a negative optokinetic afternystagmus (OKAN II). In this condition, the SPEV occurred in the dark, "open loop." Modulation of SPEV of OKAN II depended on the direction of the nystagmus and was consistent with that observed during "closed loop" HOKS. Dynamic roll-tilt influenced SPEV evoked by HOKS in a similar way. The amplitude and the phase of SPEV depended on the frequency of vestibular oscillation and on HOKS velocity. We conclude that the change in the linear acceleration of the gravity vector with respect to the head during roll-tilt modulates the gain of SPEV depending on its direction. This modulation improves gaze stability at different image retinal slip velocities caused by head roll-tilt during centric or eccentric head movement.
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Movimientos Oculares/fisiología , Movimientos de la Cabeza/fisiología , Nistagmo Optoquinético/fisiología , Reflejo Vestibuloocular/fisiología , Percepción Espacial/fisiología , Animales , Orientación , Estimulación Física/métodos , Conejos , Estadísticas no ParamétricasRESUMEN
BACKGROUND: Pouchitis and dysplasia may affect the reservoir after restorative proctocolectomy. AIMS: To assess the suitability of confocal laser endomicroscopy for the in vivo diagnosis of mucosal changes in ileal pouch for ulcerative colitis and familial adenomatous polyposis. METHODS: Standard endoscopy and endomicroscopy were performed in 18 pouches. Confocal images were scored for the presence of villous atrophy, inflammation, ulceration, colonic metaplasia and dysplasia. Targeted biopsies were taken. Endomicroscopic and histological findings were compared. RESULTS: At standard endoscopy, the signs of pouchitis were recorded in 7/18 (38.9%) patients. At endomicroscopy, pathological features were found in 16/18 (88.9%), villous atrophy in 15/18 (83.3%), inflammation in 13/18 (72.2%), ulceration in 3/18 (16.7%), and colonic metaplasia in 12/18 (67.7%). No dysplasia was observed. At histology, abnormalities were present in 17/18 (94.4%): villous atrophy in 15/18 (83.3%), inflammation in 17/18 (94.4%), ulceration in 6/18 (33.3%), colonic metaplasia in 15/18 (83.3%). Morphological changes of the ileal pouch could be predicted with an accuracy of 94.4% (95% CI: 74.2-99.0). The k-value for intra- and interobserver agreement was 0.93 and 0.78, respectively. CONCLUSIONS: Endomicroscopy may be helpful in the evaluation of morphologic changes in ileal pouch. The small size of the population sample requires further studies for the results to be confirmed.
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Íleon/patología , Mucosa Intestinal/patología , Microscopía Confocal , Proctocolectomía Restauradora , Poliposis Adenomatosa del Colon/patología , Poliposis Adenomatosa del Colon/cirugía , Adulto , Anciano , Colitis Ulcerosa/patología , Colitis Ulcerosa/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The tyrosine kinase Src is frequently activated in advanced human prostate carcinomas and its activation correlates with tyrosine phosphorylation of the RNA-binding protein Sam68. Herein, we have investigated the expression and function of Sam68 in human prostate cancer cells. Analysis of specimens obtained from 20 patients revealed that Sam68 is upregulated at the protein level in 35% of the samples. Real-time polymerase chain reaction confirmed the results at the mRNA level in most patients. Downregulation of Sam68 by RNAi in LNCaP prostate cancer cells delayed cell cycle progression and reduced the proliferation rate. Moreover, depletion of Sam68 sensitized cells to apoptosis induced by DNA-damaging agents. Similarly, stable cell lines expressing a truncated GFP-Sam68(GSG) protein displayed reduced growth rates and higher sensitivity to cisplatin-induced apoptosis. Microarray analyses revealed that a subset of genes involved in proliferation and apoptosis were altered when Sam68 was knocked down in LNCaP cells. Our results indicate that Sam68 expression supports prostate cancer cells proliferation and survival to cytotoxic agents.
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Proteínas Adaptadoras Transductoras de Señales/fisiología , Proteínas de Unión al ADN/fisiología , Neoplasias de la Próstata/patología , Proteínas de Unión al ARN/fisiología , Proteínas Adaptadoras Transductoras de Señales/química , Proteínas Adaptadoras Transductoras de Señales/genética , Anciano , Apoptosis , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Próstata/metabolismo , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/genéticaRESUMEN
Takayasu's arteritis is rarely reported associated with Crohn's disease in the English world literature. A case of Takayasu's arteritis type V in a young female affected by Crohn's disease is presented and the pathophysiology mechanism, and the clinical and diagnostic aspects are underlined. Surgical strategy is discussed.
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Enfermedad de Crohn/complicaciones , Arteritis de Takayasu/complicaciones , Adulto , Angiografía , Angioplastia/métodos , Enfermedad de Crohn/diagnóstico por imagen , Enfermedad de Crohn/cirugía , Femenino , Estudios de Seguimiento , Humanos , Enfermedades del Íleon/complicaciones , Enfermedades del Íleon/cirugía , Ileostomía , Obstrucción Intestinal/complicaciones , Obstrucción Intestinal/cirugía , Arteria Renal/diagnóstico por imagen , Arteria Subclavia/diagnóstico por imagen , Arteritis de Takayasu/diagnóstico por imagen , Arteritis de Takayasu/terapia , Factores de Tiempo , Arteria Vertebral/diagnóstico por imagenRESUMEN
CONCLUSION: The findings of this study suggest that acoustic spatial perception during head movement is achieved by the vestibular system, which is responsible for the correct dynamic of acoustic target pursuit. OBJECTIVE: The ability to localize sounds in space during whole-body rotation relies on the auditory localization system, which recognizes the position of sound in a head-related frame, and on the sensory systems, namely the vestibular system, which perceive head and body movement. The aim of this study was to analyse the contribution of head motion cues to the spatial representation of acoustic targets in humans. MATERIAL AND METHODS: Healthy subjects standing on a rotating platform in the dark were asked to pursue with a laser pointer an acoustic target which was horizontally rotated while the body was kept stationary or maintained stationary while the whole body was rotated. The contribution of head motion to the spatial acoustic representation could be inferred by comparing the gains and phases of the pursuit in the two experimental conditions when the frequency was varied. RESULTS: During acoustic target rotation there was a reduction in the gain and an increase in the phase lag, while during whole-body rotations the gain tended to increase and the phase remained constant. The different contributions of the vestibular and acoustic systems were confirmed by analysing the acoustic pursuit during asymmetric body rotation. In this particular condition, in which self-motion perception gradually diminished, an increasing delay in target pursuit was observed.
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Percepción de Movimiento , Localización de Sonidos/fisiología , Acústica , Adulto , Femenino , Cabeza/fisiología , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Percepción Espacial/fisiologíaRESUMEN
OBJECTIVE: To investigate the influence of gaze eccentricity on movement perception during asymmetric vestibular stimulation. MATERIAL AND METHODS: Subjects (n = 10) were placed on a rotating platform and oscillated asymmetrically in the dark. Subjects were asked to reproduce with a pointer the location in space of a light spot that was turned off at the beginning of the oscillation. The target was presented in centric and eccentric (0 degrees, 20 degrees and 40 degrees) positions. RESULTS: In the centric position a large shift from the real position of the target was observed in the opposite direction to that of the faster vestibular stimulation. The shift increased when the target was placed eccentrically toward the slower vestibular stimulation side and decreased when it was placed in the opposite direction. CONCLUSION: The dependence of rotation perception on the target position suggests that the eye deviation, imposed by the eccentricity of the target, is able to influence the perception of body movement and may modulate the internal reference frame.
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Movimientos Oculares/fisiología , Movimiento/fisiología , Percepción/fisiología , Adulto , Electrooculografía , Femenino , Humanos , Cinestesia , Masculino , Persona de Mediana Edad , Rotación , Pruebas de Función VestibularRESUMEN
BACKGROUND: Erectile dysfunction (ED), the inability to achieve or maintain an erection sufficient for satisfactory sexual activity, is one of the most common sexual dysfunctions in men. ED may have a dramatic impact on the quality of life of many men and their partners. OBJECTIVES: The aim of this systematic review was to evaluate and summarise the effectiveness and safety of PGE1 in the treatment of erectile dysfunction. SEARCH STRATEGY: We searched the Cochrane MS Group Trials Register (June 2003), the Cochrane Central Register of Controlled Trials (issue 2, 2003), MEDLINE (January 1966 - June 2003), EMBASE (January 1988 - June 2003) and reference lists of articles. We also undertook handsearching and contacting trialists and pharmaceutical companies. SELECTION CRITERIA: All unconfounded, double blind, randomised controlled trials comparing PGE1 and placebo treatment in participants with ED of different aetiology were considered. Primary outcomes were: (a) patient and partner satisfaction measured by means of a self-assessment; (b) quality of life and (c) safety assessment. Both parallel group and cross-over design trials were considered for inclusion. DATA COLLECTION AND ANALYSIS: All the reviewers independently selected articles for inclusion, assessed the trials' quality and extracted the data. Study authors were contacted for additional information. MAIN RESULTS: Four trials involving 1.873 people, heterogeneous with respect to aetiology of ED, were included. Study design was two cross-over and two parallel group trials. Only the latter provided adequate data for meta-analyses. PGE1 was effective during follow-up in the "at least one successful intercourse" outcome (Peto Odds Ratio, OR 7.22, 95% CI. 5.68-9.18) and "number of successful intercourse/number of PGE1 administrations" (Peto Odds Ratio, OR 6.46, 95% CI. 5.95-7.01). One cross-over study reported "at least one successful intercourse" in 63.6% of participants with at least one dose of PGE1 (P < 0.01 for each active dose versus placebo). In the other cross-over study, only one of three treatment groups conducted a self-evaluation (55.5%: "good" or "excellent" response). Adverse effects were most frequent in the treated groups and occurred more often and intensely as doses increased. Penile pain (Peto OR 7.39, 95% CI. 5.40-10.12) and minor urethral trauma (Peto OR 3.79, 95% CI. 1.88-7.65) were predominant. REVIEWERS' CONCLUSIONS: PGE1 was beneficial for many participants with ED of different aetiology. Adverse effects were proportional to dosage, albeit never serious. The use of PGE1 in ED could have been better interpreted if its effectiveness were compared by aetiology and with different forms of administrations, a longer follow-up were considered and more emphasis given to patient/partner relationships and quality of life.
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Alprostadil/uso terapéutico , Disfunción Eréctil/tratamiento farmacológico , Vasodilatadores/uso terapéutico , Alprostadil/efectos adversos , Humanos , Masculino , Ensayos Clínicos Controlados Aleatorios como Asunto , Vasodilatadores/efectos adversosRESUMEN
This paper deals with a procedure to compensate for mismatched recording conditions in forensic speaker recognition, using a statistical score normalization. Bayesian interpretation of the evidence in forensic automatic speaker recognition depends on three sets of recordings in order to perform forensic casework: reference (R) and control (C) recordings of the suspect, and a potential population database (P), as well as a questioned recording (QR) . The requirement of similar recording conditions between suspect control database (C) and the questioned recording (QR) is often not satisfied in real forensic cases. The aim of this paper is to investigate a procedure of normalization of scores, which is based on an adaptation of the Test-normalization (T-norm) [2] technique used in the speaker verification domain, to compensate for the mismatch. Polyphone IPSC-02 database and ASPIC (an automatic speaker recognition system developed by EPFL and IPS-UNIL in Lausanne, Switzerland) were used in order to test the normalization procedure. Experimental results for three different recording condition scenarios are presented using Tippett plots and the effect of the compensation on the evaluation of the strength of the evidence is discussed.
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Medicina Legal , Reconocimiento en Psicología , Habla , Teorema de Bayes , Bases de Datos como Asunto , Humanos , Funciones de Verosimilitud , Procesamiento de Señales Asistido por ComputadorRESUMEN
In this paper, we analyse mismatched technical conditions in training and testing phases of speaker recognition and their effect on forensic human and automatic speaker recognition. We use perceptual tests performed by non-experts and compare their performance with that of a baseline automatic speaker recognition system. The degradation of the accuracy of human recognition in mismatched recording conditions is contrasted with that of the automatic system under similar recording conditions. The conditions considered are of public switched telephone network (PSTN) and global system for mobile communications (GSM) transmission and background noise. The perceptual cues that the human subjects use to perceive differences in voices are studied along with their importance in different conditions. We discuss the possibility of increasing the accuracy of automatic systems using the perceptual cues that remain robust to mismatched conditions. We estimate the strength of evidence for both humans and automatic systems, calculating likelihood ratios using the perceptual scores for humans and the log-likelihood scores for automatic systems.
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Medicina Legal , Reconocimiento en Psicología , Habla , Teorema de Bayes , Señales (Psicología) , Bases de Datos como Asunto , Humanos , Funciones de Verosimilitud , Curva ROC , Procesamiento de Señales Asistido por ComputadorRESUMEN
Familial adenomatous polyposis is an autosomal dominated inherited disease, caused by the mutation of the tumour suppressor gene adenomatous polyposis coli on chromosome 5. Despite being a rare disorder, accounting for some 1% of colorectal cancers, it represents an interesting model of hereditary disease, because of its intrinsic characteristics, conventionally defined by the presence of more than 100 colorectal polyps, as well as extra-colon manifestations, the attenuated form of the disease, genetic aspects, the inevitable progression to colorectal cancer and hence the correct therapy to treat or prevent the fatal evolution of the disease. Surgical treatment is based above all on two techniques: ileorectal anastomosis, which requires careful surveillance of rectal remnant, and ileal pouch-anal anastomosis, which totally eradicates the disease. The suitability of using these two techniques is discussed in view of new genetic and clinical findings, acquired from personal experience and from the literature.
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Poliposis Adenomatosa del Colon/cirugía , Anastomosis Quirúrgica , Humanos , Selección de Paciente , Proctocolectomía Restauradora , Factores de TiempoRESUMEN
OBJECTIVE: To assess the effect of disease pattern and involvement of the margins on early and late results of enteric resections with hand-sewn anastomosis for Crohns disease. BACKGROUND: Bowel sparing is one of the aims of the surgery for CD. When strictureplasties are not possible, "minimal surgery" (the resection just of the grossly involved tract of bowel) is the current choice. METHODS: One hundred and forty-six cases of resections in 128 patients were performed in the years 1991-2001. We investigated if there is a relationship between disease pattern (perforating and non-perforating) or hystologic involvement of the margins and recurrence (reoperation for recurrent preanastomotic disease). Hand-sewn anastomosis were performed almost in all the cases; we compared the results with the main series of stapled and hand-sewn sutures. RESULTS: Nine surgical complications occurred (7%), requiring six relaparotomies and three conservative treatments. Overall rate of recurrence (median follow-up 44 months) is 17%: 9% in patients with non perforating disease and 19% in patients with perforating disease. The rate of recurrence is 6% in the group of patients with involved margins and 23% in the group with non involved margins. CONCLUSIONS: Limited surgery for CD doesn't increase rate of recurrence; the involvement of margins is not a risk factor for early reoperation. Hand-sewn anastomosis seem to be as safe as stapled ones.
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Enfermedad de Crohn/cirugía , Adolescente , Adulto , Anciano , Anastomosis Quirúrgica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/epidemiología , Pronóstico , Recurrencia , Factores de RiesgoRESUMEN
BACKGROUND: Increasing numbers of intestinal carcinomas in patients affected by Crohn's disease have been reported by several authors, even if the strength of this associations (age, longstanding of the disease, its characteristics and distribution) still has to be elucidated. METHODS: From January 1992 to July 2000, 130 patients with Crohn's disease were submitted to surgery. RESULTS: Four patients showed an associated intestinal carcinoma at operation, in 3 cases located in the ileum, and in 1 case in the colon. Patients' mean age was 54 years. Mean duration time of the Crohn's disease was 7 years. One patient died 3 months after surgery for disseminated peritoneal carcinomatosis, whereas 3 patients are still alive with malignancy free at 5, 8, and 11 years after the tumor resection. CONCLUSIONS: These results suggest the difficulty in recognizing patients with Crohn's disease who are at risk for intestinal carcinoma. Longstanding disease, previous intestinal exclusion surgery, enterocutaneous or other types of fistulas should be considered for the development of cancer. Therefore, the prognosis may be good if early diagnosis and treatment are made.
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Neoplasias del Colon/etiología , Enfermedad de Crohn/complicaciones , Neoplasias del Íleon/etiología , Anciano , Niño , Neoplasias del Colon/cirugía , Femenino , Humanos , Neoplasias del Íleon/cirugía , Masculino , Persona de Mediana EdadRESUMEN
We report the first case known to us of a synchronous isolated splenic metastasis from colon carcinoma in a 52-year-old woman operated on splenectomy, left colectomy, and ileal resection. The patient died of diffuse carcinomatosis 1 year after the operation. Splenectomy for isolated splenic metastasis from colon carcinoma is justified, and serum tumor markers are useful to detect metastases early during the follow-up, as in our report.
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Adenocarcinoma/secundario , Neoplasias del Colon/patología , Neoplasias del Bazo/secundario , Femenino , Humanos , Persona de Mediana EdadRESUMEN
The influence of neck and leg proprioceptive inputs on optokinetic-induced quick phases was studied in humans. Ten subjects received unidirectional horizontal optokinetic stimulation (10-20%/s) during sinusoidal neck, leg and combined neck + leg proprioceptive stimulation. The optokinetic reflex was measured by electro-oculography. Neck stimulation induced a shift in the nystagmus beating field in the opposite direction to body movement (gain 0.3 0.4, phase 140-180 degrees). The beating field shift resulted totally from the amplitude and frequency modulation of optokinetic quick phases, as slow phases were not affected. Leg proprioceptive stimulation induced a similar effect, but the phase of the response lagged by approximately 90 degrees compared with that of neck response. With combined neck + leg stimulation, the amplitude of the effect was a sum of the separate effects, but the phase coincided with that of the leg response. This suggests that neck and leg proprioceptive signals do not add linearly and that the leg signal determines the time of the response.
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Nistagmo Optoquinético/fisiología , Propiocepción/fisiología , Adulto , Electronistagmografía , Femenino , Movimientos de la Cabeza/fisiología , Humanos , Pierna/inervación , Masculino , Cuello/inervación , Orientación/fisiología , Valores de Referencia , Reflejo Vestibuloocular/fisiología , Procesamiento de Señales Asistido por Computador , Pruebas de Función VestibularRESUMEN
Biopsy samples of the human midpalatal suture, obtained from patients (age range: 10 and 30 yrs), were embedded in resin, cut with ultramicrotome and analyzed at light microscopy. The sutural connective tissue was made up of fibroblasts, collagen fibers, capillaries and nerve fibers. The sutural bone was made up of lamellar and bundle bone which alternated along both sides of the sutural connective tissue. No osteoblasts or osteoclasts were found, no signs of synostosis were ever detected. Our findings suggest that the lamellar bone replaces bundle bone when the suture is no longer involved in the growth of the palatal bones. The absence of bone remodelling shows that the sutures, at the time of sampling, were in a resting stage. Tissue architecture and cell types, so similar in samples from patients of such different ages, lead us to suppose that the sutures under examination are subject in time to very slow bone turnover.
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Hueso Paladar/anatomía & histología , Adolescente , Adulto , Biopsia , Capilares , Niño , Colágeno/análisis , Tejido Conectivo/anatomía & histología , Fibroblastos , Humanos , Fibras Nerviosas , Hueso Paladar/irrigación sanguínea , Hueso Paladar/inervaciónRESUMEN
Proprioceptive input arising from torsional body movements elicits small reflexive eye movements. The functional relevance of these eye movements is still unknown so far. We evaluated their slow components as a function of stimulus frequency and velocity. The horizontal eye movements of seven adult subjects were recorded using an infrared device, while horizontal rotations were applied at three segmental levels of the body [i.e., between head and shoulders (neck stimulus), shoulders and pelvis (trunk stimulus), and pelvis and feet (leg stimulus)]. The following results were obtained: (1) Sinusoidal leg stimulation evoked an eye response with the slow component in the direction of the movement of the feet, while the response to trunk and neck stimulation was oriented in the opposite direction (i.e., in that of the head). (2) In contrast, the gain behavior of all three responses was similar, with very low gain at mid- to high frequencies (tested up to 0.4 Hz) but increasing gain at low frequencies (down to 0.0125 Hz). We show that this gain behavior is mainly due to a gain nonlinearity for low angular velocities. (3) The responses were compatible with linear summation when an interaction series was tested in which the leg stimulus was combined with a vestibular stimulus. (4) There was good correspondence of the median gain curves when eye responses were compared with psychophysical responses (perceived body rotation in space; additionally recorded in the interaction series). However, correlation of gain values on a single-trial basis was poor. (5) During transient neck stimulation (smoothed position ramp), the neck response noticeably consisted of two components -- an initial head-directed eye shift (phasic component) followed by a shift in the opposite direction (compensatory tonic component). Both leg and neck responses can be described by one simple, dynamic model. In the model the proprioceptive input is fed into the gaze network via two pathways which differ in their dynamics and directional sign. The model simulates either leg or neck responses by selecting an appropriate weight for the gain of one of the pathways (phasic component). The interaction results can also be simulated when a vestibular path is added. This model has similarities to one we recently proposed for human self-motion perception and postural control. A major difference, though, is that the proprioceptive input to the gaze-stabilizing network is weak (restricted to low velocities), unlike that used for perception and postural control. We hold that the former undergoes involution during ontogenesis, as subjects depend on the functionally more appropriate vestibulo-ocular reflex. Yet, the weak proprioceptive eye responses that remain may have some functional relevance. Their tonic component tends to stabilize the eyes by slowly shifting them toward the primary head position relative to the body support. This applies solely to the earth-horizontal plane in which the vestibular signal has no static sensitivity.