摘要:

THE AESTHETIC AND functional morbidity associated with facial palsy is significant. Fortunately, corneal exposure and ulceration with the potential for the loss of visual acuity can be minimized by eyelid procedures such as gold weight implantation and horizontal eyelid shortening. Although primarily designed for restoration of eyelid function, these procedures also improve ocular cosmesis. However, uncertainty remains regarding the indications for eyelid surgery: When should surgery be performed, in whom, and which procedure(s)? On the basis of our series of 60 patients evaluated for facial paralysis, guidelines for the management of the paralyzed eyelids after iatrogenic injury to the facial nerve are proposed.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

INTERLEUKIN-1 (IL-1) PLAYS A controversial role in the immune response. Besides its activation of immune cells and juvenile central nervous system cells, monocyte-derived IL-1 may be able to stimulate the malignant transformation and proliferation of glial brain tumor cells expressing IL-1 receptors. The aim of this study was to determine the growth pattern and the IL-1β release of long-term cultured peripheral blood monocytes of glioma patients. At 6- to 7-day intervals, the vital monocytes, characterized by CD14 immunophenotyping, were counted. By the use of a specific IL-1β enzyme-linked immunosorbent assay, the IL-1β content of monocyte culture supernatants derived from 13 subjects with glioma and from 12 controls were compared at Days 7, 21, and 100 of culture. Cell clusters of monocytes derived from glioblastoma patients survived more than 250 days in culture, whereas control monocytes survived only up to 114 days. The IL-1β release of glioma-associated peripheral blood monocyte cultures was about 50 times higher as compared with control monocyte cultures. Dexamethasone treatment at the time of blood sampling and recurrences of the gliomas did not influence the increase in the IL-1β expression of glioma monocytes. It seemed that at least subsets of glioma-associated blood monocytes, although they had been removed from the circulation, remained activated for a long period of time. We conclude that increased IL-1β production of glioma-associated peripheral blood monocytes and their longevity in vitro may be features of aberrant immune cell subsets. In future studies, the exact phenotyping of monocyte subsets will be mandatory.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THE CEREBROPROTECTIVE EFFECTS of mild hypothermia have been extensively studied in various animal models of ischemia, but the mechanism by which mild hypothermia diminishes ischemic injury is not well understood. Nitric oxide (NO) has been implicated as a mediator of glutamate excitotoxicity in primary neuronal cultures, and its synthesis is acutely increased during focal ischemia in vivo. To evaluate possible mechanisms of hypothermic neuroprotection, we measured markers of NO synthesis–nitrite and cyclic guanosine monophosphate (cGMP) levels and NO synthase activity–during right middle cerebral artery occlusion (MCAO) in the rat under normothermic (36.5°C) and mild hypothermic (33°C) conditions. There was a significant increase in nitrite concentration in the right hemisphere versus the left under normothermic conditions at 10 and 20 minutes after MCAO (P< 0.01), with a return to baseline levels by 60 minutes. The increase in cortical nitrite levels in the right hemisphere versus the left was not observed with mild hypothermia. There was a threefold increase in cGMP synthesis in the normothermic right cortex 10 minutes after MCAO (P< 0.05). This rise in cGMP did not occur in hypothermic animals, and the right to left cortical disparity in cGMP production was abolished. Finally, the significant increase in NO synthase activity seen in the normothermic ischemic cortex was absent in hypothermic rats (P< 0.05). These results suggest that mild hypothermia (33°C) modulates the burst of nitric oxide synthesis during cerebral ischemia and may account, at least partially, for its cerebroprotective effects.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

NEUROTRANSMITTER RELEASE DURING cerebral ischemia has been extensively studied and is thought to play a key role in excitotoxic neuronal death. The changes in neurotransmitter release and its metabolism may reflect changes in cellular metabolism during ischemia. The purpose of this study is to assess alterations in extracellular dopamine and serotonin and their metabolites under varied degrees of ischemia in rat striatum to elucidate the pathophysiology of cerebral ischemia. Twenty rats were used to induce varied forebrain ischemia by means of bilateral common carotid artery occlusion along with hemorrhagic hypotension. Cerebral blood flow (CBF) in the striatum was measured every 40 minutes by methods of hydrogen clearance and maintained within certain ranges for 6 hours. Dopamine, serotonin, and their metabolites were measured every 20 minutes by in vivo microdialysis. Varying degrees of ischemia were obtained, ranging from 9.4 to 81.3% of control CBF. The animals were divided into three groups according to CBF levels measured 20 minutes after the induction of ischemia. In the mild ischemia group (n = 5), CBF ranged from 65 to 88% of baseline levels and resulted in only a slight increase of dopamine. In the moderate ischemia group (n = 10), CBF ranged from 21 to 48% of baseline levels and resulted in transient increases of dopamine (24-fold) and serotonin (5-fold). In the severe ischemia group (n = 5), CBF was below 14% of baseline levels and resulted in marked increases in dopamine (462-fold) and serotonin (225-fold). These alterations remained elevated for 3 hours. An analysis for the maximum release of dopamine showed a logarithmic linear correlation with CBF (r= 0.912), whereas serotonin showed a threshold-like increase at lower values of CBF. The levels of metabolites of these neurotransmitters also decreased according to the degree of ischemia, and dopaminergic metabolite levels decreased more than serotonergic metabolite levels. Under severe ischemia, all of the metabolites decreased to levels less than 30% of the control value. These results suggest that the metabolism of dopamine and serotonin is affected not only under conditions of severe ischemia but also under moderate ischemia. However, under severe ischemia, both dopaminergic and serotonergic systems are markedly affected, whereas under moderate ischemia, the dopaminergic system appears to be more vulnerable.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THE AIM OF the study was to correlate changes in transcranial Doppler blood flow velocity wave form in the basilar artery with cortical red blood cell flux measured with a laser Doppler flowmeter during hemorrhage-induced hypotension in anesthetized and ventilated New Zealand rabbits. Although systolic flow velocity and flux exhibited an autoregulatory threshold at 45 mm Hg, diastolic flow velocity started to fall when mean arterial blood pressure fell below 65 mm Hg. The difference between the mean arterial blood pressure at which diastolic blood flow velocity decreases and the pressure at which mean flux decreases is the difference between systolic and diastolic blood pressure. The increasing divergence between systolic and diastolic flow velocities was reflected in an increase in the amplitude of blood flow velocity pulsations and pulsatility indices. An increase in flux pulsatile wave form was noted as cerebral resistive vessels dilated with hypotension.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THE DELIVERY OF nonlipophilic compounds to the brain is severely hindered by the blood-brain barrier (BBB). However, brain capillary endothelial cells, which form the BBB, do possess specific receptor-mediated transport mechanisms that potentially can be exploited as a means to transport therapeutic molecules to the brain. We have found that antibodies that bind to the transferrin receptor selectively target BBB endothelium, are transported into the brain, and can function as carriers for the delivery of compounds, including proteins, to the central nervous system. This drug delivery system has been used to transport nerve growth factor across the BBB in a biologically active form and at levels sufficient to prevent the degeneration of nerve growth factor-dependent neurons.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

VASCULAR COMPRESSION OF the trigeminal nerve root accounts for more than 80% of intractable cases of trigeminal neuralgia, but the pathogenesis is still debated. The authors report the ultrastructural changes in the trigeminal nerve root of a patient with trigeminal neuralgia, at the point of compression by a large, medially placed petrosal vein, and compare these with the findings in six cases of trigeminal neuralgia not related to vascular compression. Vascular compression of the trigeminal nerve root was associated with focal loss of myelin and close apposition of the demyelinated axons with few intervening astrocytic processes. No inflammatory cells were present. Immunoelectron microscopy for glial fibrillary acid protein confirmed that astrocyte processes were largely confined to the periphery of the lesion. Of the other six rhizotomy specimens, only one, from a patient with multiple sclerosis, showed demyelination with intervening astrocyte processes, perivascular lymphocytes, and lipid-laden macrophages. These findings support the hypothesis that ephaptic transmission plays a role in the pathogenesis of trigeminal neuralgia related to vascular compression.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A FURTHER MODIFICATION of our operative positioning protocol is presented, with several novel approaches to positioning that give only slightly less exposure than that obtained with the modified prone position, but that enable the entire cranial vault remodeling to be done in one operation. The addition of two techniques has obviated both the need to use the modified prone position (except in certain difficult cases) in recent years and the need to get preoperative cervical spine film evaluation. Two new operative positioning techniques that enable a large calvarial exposure are described: one (the gel-filled collar technique) focuses on the more anterior portion of the cranial vault, and the other (the angled horseshoe technique) focuses on the posterior portion; both provide an extensive exposure of the opposite portion of the calvarium.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

WOUND INFECTION AFTER lumbar, thoracic, or cervical laminectomies is a rare but potentially devastating complication. It can range in severity from superficial wound infection to an extensive wound dehiscence. The usual treatment of these wounds consists of intensive local care, debridement, and appropriate antibiotic therapy. Secondary healing can result in chronic, painful wounds that are difficult to manage and can create the potential for osteomyelitis. Seven cases of infected dehiscent laminectomy wounds are presented. Either critical structures were exposed, or the patients did not heal after secondary or delayed primary closures. In each case, full healing was attained by means of reconstruction with a regional muscle flap. We propose that muscle flap reconstruction offers an excellent alternative for the reconstruction of difficult postlaminectomy wounds.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

WE REPORT A very unusual association of multiple aneurysms in the cranial cavity and the spinal canal, anterior spinal artery syndrome, syringomyelia, and aortic arch interruption between the origins of the left common carotid artery and the left subclavian artery. A 14-year-old boy with a history of 2 years of flaccid paraplegia and rectal and urinary incontinence after two spontaneous subarachnoid hemorrhages was encountered in August 1993. Through extensive physical and neuroradiological investigation, an association was found. Because almost all infants with aortic arch interruption die within the first month of life, this older patient gave us an opportunity to study the collateral network and the effect of hemodynamic abnormality on the central nervous system. For treatment, we believe that surgery should be directed to the hemodynamic abnormality of the aortic arch interruption. After bypass surgery from the ascending aorta to the abdominal aorta with an artificial vessel graft, the patient had some neurological improvement, as demonstrated by the sensation level lowering from T7 to L1.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID