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991.
992.
RC Knowlton KD Laxer MJ Aminoff TP Roberts ST Wong HA Rowley 《Canadian Metallurgical Quarterly》1997,42(4):622-631
The goals of this study were to determine (1) the yield of magnetoencephalography (MEG) according to epilepsy type, (2) if MEG spike sources colocalize with focal epileptogenic pathology, and (3) if MEG can identify the epileptogenic zone when scalp ictal electroencephalogram (EEG) or magnetic resonance imaging (MRI) fail to localize it. Twenty-two patients with mesial temporal (10 patients), neocortical temporal (3 patients), and extratemporal lobe epilepsy (9 patients) were studied. A 37-channel biomagnetometer was used for simultaneously recording MEG with EEG. During the typical 2-3-hour MEG recording session, interictal epileptiform activity was observed in 16 of 22 patients. MEG localization yield was greater in patients with neocortical epilepsy (92%) than in those with mesial temporal lobe epilepsy (50%). In 5 of 6 patients with focal epileptogenic pathology, MEG spike sources were colocalized with the lesions. In 11 of 12 patients with nonlocalizing (ambiguous abnormalities or normal) MRI, MEG spike sources were localized in the region of the epileptogenic zone as ultimately defined by all clinical and EEG information (including intracranial EEG). In conclusion, MEG can reliably localize sources of spike discharges in patients with temporal and extratemporal lobe epilepsy. MEG sometimes provides noninvasive localization data that are not otherwise available with MRI or conventional scalp ictal EEG. 相似文献
993.
This paper attempts to shed some light on the recent debate between those who advocate a reformed medical geography and those who respond that reform is not necessary. We show that disease ecology and a reformist alternative display certain tendencies in the ways in which they address issues of health and disease. We use the example of geographic variations in infant mortality rates to show how two non-positivist perspectives from social theory, political economy and humanism, support a reformist viewpoint, while also acknowledging the value of a complementary disease ecology approach. Two concepts, the social construction of health and illness and social relevance, are used to portray the political economy approach; humanism is described in terms of the meaning of individual experience and the importance of place. The paper concludes with a discussion of the respective roles of disease ecology and a reformist approach in models of infant mortality and a summary of the main differences between the two perspectives. 相似文献
994.
995.
A 34 year-old man presented with hemoperitoneum from a spontaneously ruptured spleen. At laparotomy, a 5-cm diameter splenic cyst was found to be ruptured. Histological examination confirmed the diagnosis of a true splenic cyst of the mesothelial type. Spontaneous rupture with hemoperitoneum is a rare but potentially lethal complication of a true splenic cyst. 相似文献
996.
Giant cervicofacial lymphatic malformation, a potentially life-threatening congenital malformation, historically has been removed in staged resections. However, complete surgical extirpation is desirable and can be achieved with the aid of a multidisciplinary team. The authors present the case of a 12-year-old girl who had an extensively enlarged cervicofacial lymphatic malformation. Effective treatment involved aggressive surgical excision, facilitated by mandibular osteotomies to provide access to the floor of the mouth, the tongue, and the pharyngeal wall. In addition, total removal of involved facial and neck skin was performed. The remaining soft tissue defect was reconstructed primarily with an abdominal musculocutaneous free flap. In the 5 years since the procedure, there has been no recurrence. Based on this experience, excision of involved skin and mandibular access osteotomies are important techniques to help completely remove cervicofacial lymphatic malformations with oral involvement, thus potentially reducing the number of recurrences. In addition, these cases require the best efforts of a multidisciplinary team to achieve a successful result so that complete and radical excision can be performed with the hope of avoiding the pitfalls of multiple resections. 相似文献
997.
Liposarcomas of the head and neck are exceedingly rare, and fewer than 90 cases have been reported in the literature. Liposarcoma of the oral cavity is an even less common entity, and to our knowledge only nine cases have been reported to date. We report the clinical and pathologic findings of a case of well-differentiated liposarcoma of the base of tongue and tonsillar fossa. The patient is a 76-year-old white man with a long-standing history of a mass in the oral cavity and hypopharynx. The mass had been resected several times over the span of 23 years, and diagnoses of lipoma, neurofibroma, mesenchymoma, and angiofibrolipoma have been rendered on different occasions. At the last admission, a polypoid mass of the left tonsillar fossa and base of tongue was resected. The tumor was multinodular and measured 2.5 cm in greatest diameter. Histologically the tumor was ill-defined with infiltrating borders and was composed predominantly of mature adipose tissue with occasional lipoblasts. A small proportion of the tumor consisted of clusters of spindle cells and pleomorphic lipoblasts. Mitotic activity was not seen. The pleomorphic cells were positive for S100 protein and negative for muscle-specific markers. Ultrastructural analysis confirmed the nature of the lipoblasts. Our case depicts the typical natural history and histologic features of liposarcoma of the oral cavity. This tumor is usually well differentiated and has a high recurrence rate and almost no tendency for metastasis. Based on our case and review of the literature, it appears that well-differentiated liposarcoma of the oral cavity can occasionally be underdiagnosed because of the low mitotic activity and long latent period between the original diagnosis and first recurrence. 相似文献
998.
Right ventricular assist devices are an important part of the armamentarium of cardiac surgeons for the treatment of right-sided circulatory failure after cardiac transplantation or insertion of a left ventricular assist device. However, right ventricular assist device insertion can be technically challenging in the setting of pulmonary hypertension because of a number of concomitant anatomic and physiologic phenomena. We present a technique for the insertion of the right ventricular assist device outflow cannula that is easier and faster to insert, and safer to explant, especially if cardiopulmonary bypass is to be avoided. 相似文献
999.
Auxin represents one of the most important classes of signalling molecules described in plants. Auxins regulate several fundamental cellular processes including division, elongation and differentiation. Indole-3-acetic acid (IAA), the principal form of auxin in higher plants, is first synthesized within young apical tissues, then conveyed to its basal target tissues by a specialized delivery system termed polar auxin transport. The polarity of IAA movement represents one of the most novel aspect of auxin signalling. IAA transport has been demonstrated to involve auxin influx and efflux carrier activities. The adoption of a mutational approach in the model plant Arabidopsis thaliana has led to the identification of a number of genes which encode components for, or regulate the activity of, the auxin transport machinery. This paper will review the advances being made in identifying and characterizing these auxin transport-related gene products and discuss their importance within the context of Arabidopsis development. 相似文献
1000.
N Hayashi JN Weinstein ST Meller HM Lee KF Spratt GF Gebhart 《Canadian Metallurgical Quarterly》1998,23(8):877-885
STUDY DESIGN: The effect of epidural injection of betamethasone or bupivacaine was investigated in an animal model of lumbar radiculopathy. OBJECTIVE: To investigate the effects of an epidural steroid (betamethasone) or a local anesthetic (bupivacaine) in an animal model of radiculopathy produced by nerve root irritation. SUMMARY OF BACKGROUND DATA: Epidural injections are commonly used for the treatment of low back pain and sciatica. However, efficacy remains controversial, and there is a paucity of basic information to support clinical use or the injections. METHODS: Fifty-one rats were used. The left L4 and L5 nerve roots were loosely ligated with chromic gut, and either betamethasone, bupivacaine, betamethasone in combination with bupivacaine, or saline was injected using an epidurally placed catheter. The effects of epidural injection were evaluated using response to noxious stimuli and immunohistochemical methods. RESULTS: In betamethasone-treated rats (either alone or in combination with bupivacaine), thermal hyperalgesia was significantly less (P < 0.010 after surgery than that in saline- or bupivacaine-treated groups, in which the hyperalgesia was maximum at 2-3 postoperative weeks before resolving 5 weeks after surgery. Immunohistochemical analysis did not correlate with these results. CONCLUSIONS: Epidural steroid injection has a significant effect on the thermal hyperalgesia produced in a model of radiculopathy, which may provide clinical support for advocates of epidural steroids. 相似文献