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31.
Functional magnetic resonance studies of the reorganization of the human hand sensorimotor area after unilateral brain injury in the perinatal period. 总被引:6,自引:0,他引:6
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Y Cao E M Vikingstad P R Huttenlocher V L Towle D N Levin 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(20):9612-9616
Functional magnetic resonance imaging was used to map the hand sensorimotor area of hemiparetic adolescents and young adults who had suffered unilateral brain damage in the perinatal period. Unlike normal subjects, who exhibit cortical activation primarily contralateral to voluntary finger movements, the hemiparetic patients' intact hemispheres were equally activated by contralateral and ipsilateral finger movements. Our findings are consistent with previous clinical observations and animal experiments which suggest that the immature brain is able to reorganize in response to focal injury. 相似文献
32.
G. A. Broderick P. A. Longhurst P. E. Juniewicz A. J. Wein R. M. Levin 《World journal of urology》1994,12(5):245-248
Summary Benign prostatic hyperplasia (BPH) is a major medical problem in the United States. The primary medical complication of BPH is progressive obstruction of the urethra and a subsequent in reduction the ability or the bladder to empty efficiently. The urodynamic characteristics associated with BPH include hyperreflexia, increased bladder capacity, increased frequency, decreased flow rate, and increased residual volume. Although there currently are individual animal models of prostate enlargement and animal models of partial outlet obstruction, there is no model of progressive obstruction secondary to prostate enlargement. The primary objective of the current study was to develop a canine model of BPH that would secondarily result in partial urethral obstruction and impaired urodynamics. Our model consists of encapsulating the prostate in a nylon mesh to prevent the growth of the prostate into the peritoneal cavity and then treating the dog with steroids to induce prostate growth and subsequently produce urethral constriction. The results demonstrate that encapsulation of the dog prostate and administration of steroids results in an increase in prostate mass simultaneously with an increase in urethral pressure and in changes in bladder contraction consistent with the presence of partial outlet obstruction. This preliminary study demonstrates that by preventing the outward growth of the steroid-stimulated prostate, urethral obstruction resembling BPH can be produced.This work was supported in part by grants from the Veterans Administration, NIH grants RO-1-DK 26508 and RO-1-DK33559, and the Stterling Winthrop Pharmaceuticals Research Division. 相似文献
33.
Current status of magnetic resonance imaging of the wrist. 总被引:2,自引:0,他引:2
P L Munk A D Vellet M F Levin L S Steinbach C A Helms 《Journal l'Association canadienne des radiologistes》1992,43(1):8-18
Conventional imaging of the wrist has relied heavily on plain radiography, tomography, fluoroscopy and arthrography. More recently, computed tomography and magnetic resonance imaging (MRI) have been added to this armamentarium. In this article the authors review the normal anatomy of the wrist and demonstrate a variety of pathologic conditions that can be assessed with MRI, including avascular necrosis and tears of the intrinsic and the extrinsic ligaments and the triangular fibrocartilage. MRI of the wrist is still evolving rapidly, and its place in the work-up of wrist disorders is only now being defined. 相似文献
34.
Tumors of the hypothalamus present with a variety of clinical syndromes. Such syndromes appear to be both age and histology dependent. The diencephalic syndrome, an entity classically seen in infancy, presents as failure to thrive. In essentially all cases the pathologic substrate is a tumor with a predominance of gliomas. The traditional approach to treatment of the diencephalic syndrome has been surgery both for decompression and pathologic diagnosis followed by irradiation. Because of the tumor location, surgery is often confined to biopsy rather than radical extirpation. Furthermore, in infancy focal brain irradiation is not without significant morbidity. Within this context, we would like to present a case discussion regarding a 27-month-old boy with a hypothalamic-midbrain protoplasmic glioma treated with primary chemotherapy after surgical biopsy and pathologic documentation. The schedule of drugs utilized was based on the hypothesis of biochemical modulation of nitrosourea chemotherapy. Successful response to therapy was documented by sequential computed tomography (CT) studies and serial neurologic examinations beginning at age 5 months and every 2 months thereafter. The response of a single patient with the diencephalic syndrome treated primarily with chemotherapy makes extrapolation premature. Rather, the authors suggest chemotherapy as an alternative to focal brain irradiation. Such therapy could be utilized either in the event of recurrent tumor or as late consolidation after primary treatment with chemotherapy. The latter approach would allow a patient to have radiation therapy deferred until a later age at which time morbidity attending brain irradiation may be minimized. 相似文献
35.
Diagnosis and treatment of sacral and retrorectal tumors. I 总被引:1,自引:0,他引:1
36.
L S Levin R D Goldner J R Urbaniak J A Nunley W T Hardaker 《Journal of orthopaedic trauma》1990,4(4):432-440
Limb salvage was successful in 25 patients treated for severe grade III upper extremity injuries. In a retrospective review of 20 men and five women, follow-up time averaged 26 months. These high-energy injuries were characterized by massive soft-tissue injury, highly comminuted fractures, and significant neurovascular injury. Farm, industrial, and vehicular accidents accounted for 80% of the cases. Over 50% of the patients had concomitant systemic and/or other significant extremity injuries. Initial treatment consisted of irrigation and debridement and fracture stabilization using external and/or internal fixation. An average of four additional surgical procedures was required to provide soft-tissue coverage and maximum possible functional recovery. Forty-eight percent of the extremities underwent free vascularized or pedicular flaps for coverage or reconstruction. At final follow-up observation, 12% of the extremities rated excellent, 20% rated good, 52% fair, and 16% were poor. Experience gained in managing these severe upper extremity fractures supports the following observations. (a) Grade III open fractures of the upper extremities are frequently associated with significant neural, vascular, and musculotendon injuries. (b) External fixation plays an important role in the stabilization of grossly contaminated fractures. (c) Residual functional disability is common, and most patients do not return to their previous occupation. (d) Staged reconstruction directed toward maximum functional return may take several years. 相似文献
37.
T Hoshino L A Rodriguez K G Cho K S Lee C B Wilson M S Edwards V A Levin R L Davis 《Journal of neurosurgery》1988,69(6):839-842
The proliferative potential of low-grade astrocytomas was estimated in 47 patients. Each patient received an intravenous infusion of bromodeoxyuridine (BUdR), 150 to 200 mg/sq m, at the time of craniotomy to label cells in deoxyribonucleic acid (DNA) synthesis; the percentage of S-phase cells, or BUdR labeling index (LI), of each tumor was determined immunohistochemically. In 29 patients (60%), the tumors had BUdR LI's of less than 1%, indicating a slow growth rate; only three (10%) of these patients died of recurrent tumor during a follow-up period of up to 3 1/2 years. In contrast, of the 18 patients (40%) whose tumors had BUdR LI's of 1% or more, 12 (67%) had a recurrence and nine died during the same follow-up period. These results show that the proliferative potential, as reflected by the BUdR LI, is an important prognostic factor that separates low-grade astrocytomas into two groups and provides a more scientific rationale for selecting treatment for individual patients. 相似文献
38.
Allan E. Siperstein M.D. Qui -Hua Zeng M.D. Elizabeth T. Gum M.S. Kenneth E. Levin M.D. Orlo H. Clark M.D. 《World journal of surgery》1988,12(4):528-532
Prior studies in our laboratory have shown that human thyroid neoplasms have a greater adenylate cyclase activity in response to thyroid stimulating hormone (TSH) than does the adjacent histologically normal thyroid tissue. However, there is little information relating activity of the TSH receptor-adenylate cyclase system to the type of thyroid neoplasm. Thyroid tissue from 67 patients was divided by clinical and histological criteria into 6 categories: normal (59), benign tumors (20), stage 1 carcinoma—intrathyroidal involvement only (25), stage 2 carcinomaregional lymph node involvement (6), stage 3 and 4 carcinoma—tissue invasion or distant metastasis (11), and medullary carcinoma (3). Adenylate cyclase activity in an 8,000 x g thyroid membrane preparation was determined in the basal state and when maximally stimulated with 300 mU/ml TSH. The cyclase responsiveness was the ratio of TSH stimulated adenylate cyclase activity compared to basal adenylate cyclase activity. The cyclase responsiveness by category is: normal, 2.8±0.2 (mean ± SEM); benign, 17.9±2.4; stage 1 carcinoma, 9.2±1.9; stage 2 carcinoma, 4.0±1.0; stage 3 and 4 carcinoma, 1.6±0.4; and medullary carcinoma, 1.05±0.04 (for the neoplasms,p <0.02 by ANOVA). Tumor stage was the only correlate with this trend as other prognostic risk factors (age, sex, a history of neck irradiation, or papillary versus follicular histology) showed no difference in cyclase responsiveness. These studies demonstrate a consistent inverse correlation between adenylate cyclase responsiveness and tumor stage or aggressiveness. Cyclase responsiveness appears to have clinical application for predicting which thyroid tumors will behave aggressively.
Presented at the International Association of Endocrine Surgeons in Sydney, Australia, September, 1987.
Supported in part by the Medical Research Service of the Veterans Administration. 相似文献
Resumen Estudios previos en nuestro laboratorio han demostrado que los neoplasmas tiroideos humanos poseen una mayor actividad de adenilato ciclasa en respuesta a la administración de hormona estimulante de la tiroides (TSH) que el tejido tiroideo histológicamente normal adyacente. Sin embargo, existe muy poca información sobre la relation de la actividad del sistema receptor de TSH-adenilato ciclasa y el tipo del neoplasma tiroideo. Tejido tiroideo proveniente de 67 pacientes fue dividido mediante criterios chlínicos e histológicos en 6 categorias: normal (59), tumores benignos (20), extensión intratiroidea solamente en estado 1 (25), carcinoma-extensión ganglionar regional en estado 2 (6), carcinoma-invasión tisular o metástasis distantes en estados 3 y 4 (11), y carcinoma medular (3). La actividad de la adenilato ciclasa en una preparación de membrana tiroidea de 8,000 × g fue determinada en el estado basai y en estado de maxima estimulación con 300 mU/ml TSH. El grado de respuesta de la ciclasa fue la tasa de actividad de la adenilato ciclasa estimulada por TSH comparada con la actividad basai de la adenilato ciclasa. El grado de respuesta por categorías fue: normal, 2.8±0.2; tumor benigno, 17.9±2.4; carcinoma estado 1, 9.2±1.9; carcinoma estado 2, 4.0±1.0; carcinoma estados 3 y 4, 1.6±0.4; y carcinoma medular, 1.05±0.04 (para los neoplasmas,p < 0.02 por ANOVA). El estado del tumor apareció como el único factor de correlatión con esta gradación, ya que otros factures de pronóstico (edad, sexo, historia de irradiación cervical, histología papilar versus folicular) no demostraron diferencia en cuanto al grado de respuesta de la ciclasa. Estos estudios demuestran una consistente relación inversa entre el grado de respuesta de la adenilato ciclasa y el estado o agresividad tumoral. El grado de respuesta de la ciclasa parece tener aplicación clínica para predecir qué tumores tiroideos se habrán de comportar en forma agresiva.
Résumé Les études antérieures provenant de nos laboratoires ont démontré une augmentation de l'activité enzymatique de l'adénylate-cyclase en réponse à la thyroïd stimulating hormone (TSH) dans le tissu thyroïdien humain tumoral, par rapport au tissu thyroïdien adjacent normal. Cependant il existe peu de données concernant l'activité du système récepteur TSH/adénylatecyclase par rapport au type de tumeur de la thyroïde. Les tissus thyroïdiens provenant de 67 patients différents ont été repartis en 6 groupes selon des critères cliniques et histologiques: normal (59), tumeur bénigne (20), cancer stade 1 (intrathyroïdien uniquement) (25), cancer stade 2 (envahissement ganglionnaire régional) (6), cancer stade 3 et 4 (envahissement tissulaire avoisinant ou métastases à distance (11), et cancer médullaire (3). A partir d'une préparation de membrane thyroïdienne centrifugée à 8,000 × g, l'activité de l'adénylate-cyclase a été déterminée en l'état basai et après stimulation maximale par 300 mU/ml de TSH. La réponse enzymatique a été mesurée comme étant le rapport de l'activité stimulée par la TSH/activité basale. Les résultats selon les 6 groupes étaient (moyen±ET): tissu normal, 2.8±0.2; tumeur bénigne, 17.9±2.4; cancer stade 1, 9.2±1.9; cancer stade 2, 4.0±1.0; cancers stade 3 et 4, 1.6±0.4; et cancer médullaire, 1.05±0.04 (p < 0.02 par l'analyse de variance pour les néoplasies). Le stade tumoral était la seule variable corrélée avec l'activité enzymatique. L'activité enzymatique n'était pas corrélée avec l'âge, le sexe, les antécédents d'irradiation cervicale antérieure ou l'histologie (papillaire vs. folliculaire). Ces études montrent un rapport inversement proportionnel entre l'activité d'adénylate-cyclase et le degré d'agressivité tumorale ou le stade. La réponse d l'adénylate-cyclase paraît avoir une application clinique: prévoir quelles tumeurs thyroïdiennes auront une évolution agressive.
Presented at the International Association of Endocrine Surgeons in Sydney, Australia, September, 1987.
Supported in part by the Medical Research Service of the Veterans Administration. 相似文献
39.
Shinichiro Kitada Kumiko Kato Alan J. Wein Robert M. Levin 《Neurourology and urodynamics》1989,8(3):255-262
We were able to produce two highly reproducible experimental models (in the rabbit) that demonstrated a high degree of reflex bladder contractile activity. In one model, a somatovesical reflex was induced by touching or pinching the perineal area. This reflex may be organized through a neurogenic reflex at the spinal level. In another model, rhythmic bladder contractions were produced by distal urethral constriction in the absence of bladder distension. These rhythmic contractions were thought to be due to a supraspinal reflex. In both types of contractile reflexes, intravenous administration of hexamethonium inhibited the reflex contractile activity virtually completely, intravenous atropine inhibited over 90% of the induced contractile activity, thus suggesting that these contractions were mediated reflexly through cholinergic stimulation. These two models of reflex bladder contractions should be useful for the study of hyperreflexic bladders. 相似文献
40.
Multivariate flow cytometric analysis and sorting of mouse bone marrow cells viably stained with Hoechst 33342 (HO) was utilized to obtain a subpopulation enriched at least 30- to 60-fold for clonogenic megakaryocyte precursors (CFU-Meg). HO fluorescence intensity, forward light scatter, and perpendicular light scatter were measured on each HO-stained bone marrow cell as it passed through a dual beam flow cytometer. Cells were sorted on the basis of their light scattering and HO fluorescence intensity properties. The sorting region which included cells with high forward light scatter, low perpendicular light scatter, and low (0.1-0.65 times the modal channel) HO fluorescence intensity contained approximately 0.6% CFU-Meg. Of all CFU-Meg, 75% were contained in the light scatter gate, and 56% of all CFU-Meg were in the low HO-sorting region. This technique offers a simple, one-step procedure to obtain preparations enriched in murine clonogenic megakaryocyte precursors. 相似文献