摘要:

&NA;Pressure‐volume relations were investigated on a model aneurysm wall made of elastic tissue and collagen. The model wall had a Young's Modulus of 2 × 107dynes/cm2, approximating the elastance of fresh aneurysm walls obtained at autopsy. The model wall was fixed over the top of a glass T‐tube, 6 mm in diameter. Pressure pulse waves of water or outdated human blood entered at the bottom of the T‐tube and exited by way of a controlled resistance, while pressure was monitored by a strain gauge and recorded on an ink writer from the other arm. Incremental increases in systolic pressure produced a nonlinear N‐shaped pressure‐volume curve. There was an initial linear enlargement in volume with increased pressure until a pressure threshold was reached at a point of high nonlinear compliance. At this point there was an abrupt jump in volume (mean increase = 70 ± 14%) to a new stable equilibrium volume. A further increase in pressure (24 ± 7 mm Hg) could eventually cause aneurysm rupture. This always occurred in the thinner, more compliant part of the wall. With higher pulse rates, the jump in volume occurred at a smaller volume, whereas with thinner aneurysm walls of higher compliance the pressure threshold for a jump in volume was significantly lower. At a higher peripheral resistance there was a higher pressure threshold. The authors suggest that there is one possible mechanism that may occur in the neck of some developing human aneurysms and could explain early and rapid initial growth in size. (Neurosurgery24:722‐730, 1989

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The influence of subarachnoid hemorrhage (SAH) on vasodilatation induced by vasoactive intestinal polypeptide (VIP) was investigated in rabbit basilar arteries. VIP‐induced relaxation was measured in ring sections of the basilar arteries precontracted by 10‐5M serotonin using an isometric tension recording method. The cyclic adenosine monophosphate (cAMP) content was measured using radioimmunoassay as an indicator of the intracellular mechanism in the arterial smooth muscle cells. VIP (10‐11‐10‐6M) evoked dose‐dependent relaxation of the basilar arteries. The relaxation achieved with 10‐6M VIP was 85 ± 4% (n = 7) of the initial contractile tone in control arteries and 47 ± 5% (n = 8) in the arteries evaluated 2 days after SAH, suggesting that VIP‐induced relaxation was suppressed significantly after SAH (P< 0.01). The cAMP content was significantly higher in the basilar arteries 2 days after SAH (425 ± 48 pmol/g of tissue, n = 7) than in the control basilar arteries (194 ± 57 pmol/g of tissue, n = 7). In normal arteries, the cAMP content was increased to a significant degree by VIP (10‐6M) (325 ± 60% of control cAMP content, n = 5), whereas the increase was less in the arteries evaluated 2 days after SAH (112 ± 16% of control cAMP content, n = 5). These results suggest that SAH has an influence on cAMP metabolism in the arteries and that SAH impairs the postsynaptic mechanism of VIP‐induced dilatation of the arteries. (Neurosurgery24:731‐735, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Transsphenoidal surgery is an efficacious treatment for patients with prolactin (PRL)‐secreting adenomas, even if disrupted pituitary‐hypothalamic relationships may persist and/or a recurrence of the PRL‐secreting tumor can occur. In this paper, we analyze the long‐term follow‐up of 119 consecutively treated women who underwent transsphenoidal microsurgery for PRL‐secreting adenomas. Apparent total removal of the tumor was achieved in 98 patients who had enclosed tumors (58 with Grade‐I tumors and 40 with Grade II). In the remaining patients, the removal was considered partial. Persistent normal basal PRL levels were achieved in 61 patients who had apparent total removal of the adenoma (44 with Grade I tumors and 17 with Grade II). Of the remaining 37 patients in whom surgical removal of the adenomatous tissue was thought to be total, 30 had persistent nonevolutive, high PRL levels ranging from 21 to 196 ng/ml, without clinical and radiological signs of tumor regrowth, and 7 with PRL levels ranging from 56 to 560 ng/ml had a recurrence of the PRL‐secreting tumor. These data seem to indicate that a slightly elevated postsurgical PRL value does not imply that tumoral tissue is still present. Nontumoral conditions (i.e., a secondary empty sella) could induce functional hyperprolactinemia. (Neurosurgery24:736‐743, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Decreased somatostatin in the brains of patients with Alzheimer's disease has led to an investigation of the efficacy of neurotransmitter replacement therapy. The distribution of a somatostatin analog, octreotide, was determined after 2 to 6 days of continuous intraventricular infusion at 40 &mgr;g/h in dogs. The tissue concentration was greater than 100 ng/g wet weight in all parts of the brain, which is greater than the normal concentration of native somatostatin. There was no reduction in native somatostatin production because of the infusion of the analog. The cerebrospinal fluid octreotide concentration was 1000 times greater than the plasma concentration. The results demonstrate that neurotransmitter replacement for somatostatin can be achieved by chronic intraventricular infusion of a metabolically stable analog. (Neurosurgery24:744‐748, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The availability of transcranial Doppler sonography has resulted in an easy, noninvasive, reproducible, and highly reliable method for evaluating the flow characteristics of carotid‐cavernous sinus fistulas. It also allows the follow‐up of the effect of different interventional measures, specifically, embolization with detachable balloons. An illustrative case is reported, in which the findings of serial transcranial Doppler sonograms are correlated with findings on computed tomographic scans and angiograms. The impact of our findings on future approaches to the hemodynamic classification of these acquired vascular shunts is discussed. (Neurosurgery24:749‐753, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;A patient with subarachnoid hemorrhage (SAH) due to rupture of a saccular aneurysm arising at the origin of the intradural intraspinal vertebral artery is presented. This case shows that aneurysms at this site may be a rare cause of SAH and reinforces need for 4‐vessel angiography after SAH. (Neurosurgery24:753‐755, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;We are reporting a temporary, totally reversed motor and sensory paralysis subsequent to the intrathecal administration of 1.6 mg of morphine sulfate. This may represent an event which is not based on medication‐induced myelopathy but on cardiovascular changes occurring as a result of pain relief. (Neurosurgery24:756‐758, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Trigeminal neuralgia in its classic form is usually an isolated disease that occurs in sporadic fashion without epidemio‐logical or genetic significance. This paper discusses a family with three nontwin sisters, all of whom have classic trigeminal neuralgia occurring in early middle age with symptoms severe enough to require medical and surgical treatment. These three sisters also have one aunt with a history of severe facial pain, although this has not been medically documented. Clustering of such cases in a given family has been reported before, but is rare. The pathophysiological implications of this genetic clustering are discussed. (Neurosurgery24:758‐761, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Intraorbital paragangliomas are rare. A case of intraorbital paraganglioma with extension to the middle cranial fossa is reported. Progressive throbbing, hemicranial headaches, unilateral proptosis, and visual failure are the presenting symptoms. The computed tomographic and operative findings suggested a meningioma. Surgical removal of the tumor resulted in total relief of symptoms and recovery of vision. The pathogenesis and pathological findings are discussed. (Neurosurgery24:762‐764, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The authors report a case of acoustic neurinoma presenting as intratumoral bleeding. This is the tenth reported occurrence. The literature is reviewed. All cases that have been reported have appeared with sudden onset of headache, vomiting, and decreased levels of consciousness. Aneurysm rupture, an arteriovenous malformation, or other vascular anomalies are suspected first. Preexisting unilateral hearing impairment is a valuable clue to differential diagnosis. Contrast‐enhanced computed tomographic scans and cerebral angiograms are important tools for correct diagnosis. The tumor size (>2 cm) and the thin, dilated vessels within the tumor are considered as pathogenetic factors for bleeding. When neurological status is not stable, placement of a ventriculoperitoneal shunt followed by urgent extirpation of the tumor is indicated. (Neurosurgery24:764‐768. 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID