摘要:

During 100 autopsies of patients who had no previous endocrinological problem, selective injections of the pituitary arterial systems were performed. Pituitary glands were examined from 60 male and 40 female patients with an average age of 68 years. Detailed histological and immunocytological studies using peroxidase-antiperoxidase techniques for prolactin (PRL), adrenocorticocotropic hormone (ACTH), follicle-stimulating hormone, thyroid-stimulating hormone, and growth hormone were used. Thirty-three microadenomas were found in 27 patients; 22 were single, 4 were double, and 1 was triple. Fourteen were nonreactive to immunostaining, 10 were reactive to PRL, and 9 were reactive to ACTH. Their diameters ranged between 0.5 and 5.0 mm, and they were located mainly in the lateral wings and the peripheral zone of the anterior pituitary gland. Microvascular study revealed that 22 microadenomas (66%) had direct extraportal arterial supplies. Because the hypothalamic factors are transported to the anterior lobe through the portal vessels, this study suggests that the formation of microadenomas occurs most frequently outside the hypothalamic-hypophyseal portal system and further supports the hypothesis that pituitary adenomas may arise de novo without the influence of hypothalamic factors.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Forty-four patients underwent 45 computer-assisted stereotactic resections of intracranial metastases from various centrally located and deep-seated regions using methods described in this report and elsewhere. Gross total removal was achieved in all cases. There was no postoperative mortality (within 30 days). Postoperative neurological examinations revealed that: (a) of 26 who presented with preoperative neurological deficits, 13 were normal postoperatively, 7 were improved, 3 were unchanged, and 3 were worse; (b) 5 of 5 patients who had increased intracranial pressure preoperatively were normal postoperatively; and (c) 3 of 3 patients who had increased intracranial pressure and neurological deficit preoperatively were neurologically normal postoperatively. Nine of 10 patients who were neurologically normal preoperatively were normal postoperatively, and the other had transient upper extremity weakness after resection of a lesion in the contralateral motor strip. The 1-year survival in this group of patients was 62.5%. No local recurrence was noted in any patient. Computer-assisted stereotactic resection permits accurate localization of metastatic lesions and gross total resection from difficult locations with acceptable levels of morbidity.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The electromagnetic field focusing (EFF) probe, which is based on the principle of eddy current convergence, produces intense pinpoint heat at its point of contact with tissue. This allows cutting and vaporization of tissue and coagulation of vessels. The present experiments were conducted to study heat distribution to the surrounding tissue in brain and phantom and the effect on the brain of vaporization of intracerebral tumors in 19 rabbits. The follow-up period was as long as 47 days. The heating pattern showed a rise of temperature up to 250 degrees C at the probe tip, with minimal or no temperature increase at 2 mm and beyond. Minimal or no change was noted in the surrounding brain after tumor vaporization, indicating that this system would be safe in the vaporization of brain tumors in clinical neurosurgery.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The vasculature and capillary permeability of gliomas induced by ethylnitrosourea in Sprague-Dawley rats were studied with horseradish peroxidase and Evans blue dye. The distribution of the boron-10 compound, Na2(10)B12H11SH, which is now in clinical use for boron neutron capture therapy (BNCT) for brain tumors, was investigated quantitatively using neutron-induced alpha-autoradiography. The vasculature and the degree of capillary permeability varied widely, depending mainly on the size of the glioma, and were often heterogeneous even in the same tumor. The distribution of boron-10 also varied, correlating to capillary permeability. The boron-10 concentration and the tumor:blood concentration ratio in large and medium-sized gliomas were adequate for successful BNCT. This study suggests that the vasculature and capillary permeability of the target brain tumor exert an important influence on the therapeutic efficacy of BNCT.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Eight cases of ventral (paraclinoid) internal carotid artery aneurysms are presented. These aneurysms often challenge the surgeon because (a) they are partially or completely obscured by the optic nerve, internal carotid artery, and anterior clinoid process; (b) there is no proximal internal carotid artery control intracranially; and (c) part of the neck and fundus of the aneurysm is located within the cavernous sinus. These aneurysms, which have been classified as separate from the typical carotid-ophthalmic aneurysm group, are illustrated, and their surgical treatment and problems described.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Among the factors that determine the behavior of an intracranial aneurysm is the relationship between its volume and the size of the orifice. The investigative method described herein is the means being used to define that relationship in humans. It is a postmortem study that focuses on unruptured aneurysms. Central to the protocol was a synthetic rubber cast of the aneurysm's interior. The cast was made under normal arterial pressure so that unruptured aneurysms were reexpanded to lifelike size and shape. After the cast was removed intact from the specimen, the lumenal features recorded upon it were verified by comparison with the opened aneurysm. Working now only with the cast, the chamber was cut from the artery through its neck. The orifice area was determined by dividing it, mathematically, into many smaller, measurable forms. Chamber volume was ascertained by a fluid displacement technique. Both measurements were made with magnification and engineering instruments. Casts of ruptured or thrombosed aneurysms gave helpful morphological information, but were of limited value for measurement. The techniques are described, and examples of the initial results are presented.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

To determine whether cerebral arteries in spasm have an altered capacity to synthesize the vasoactive substances prostacyclin and thromboxane A2, we measured levels of these arachidonic acid metabolites using a primate model of vasospasm. Twenty-four cynomolgus monkeys were assigned at random to one of three groups designated sham, clot, or clot-removal. All animals underwent base line cerebral angiography and bilateral dissection of the major cerebral arteries from the arachnoid. The clot and clot-removal groups had autologous hematomas placed around the vessels to simulate subarachnoid hemorrhages. The sham group had a similar volume of saline instilled into the subarachnoid space. Twenty-four hours later, the clot-removal group underwent a second craniotomy to remove the hematomas. Seven days after the initial operation, angiography was repeated on all animals. The animals were then killed, and the cerebral arteries were removed. Basal levels of prostacyclin and thromboxane in the cerebral vessels were measured after incubation in vitro by radioimmunoassay. No detectable leukotriene C4 release by these arteries was measurable using radioimmunoassay. Angiography revealed severe cerebral vasospasm in the clot group, but not in the clot-removal or sham groups. There were no statistical differences among the groups in thromboxane release, but prostacyclin levels were significantly lower in the clot group than in the clot-removal group (P less than 0.05). It thus seems that, if an imbalance in constrictor and dilator eicosanoids occurs in association with vasospasm, this is more likely to arise from a relative lack of the vasodilator component prostacyclin than from a surplus of the vasoconstrictor thromboxane. (ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Having previously studied a static load model of cord injury in rats, we report here an evaluation of a dynamic (weight drop) technique. Under general anesthesia, Sprague-Dawley rats were subjected to a laminectomy at T12, after which a 10-g weight was dropped onto a force transducer and impounder resting on the spinal cord; the weight drop distances varied in different groups from 0 (control) in increments of 2.5 cm to a maximal height of 17.5 cm. A strain gauge attached to the force transducer yielded an oscilloscopic wave form from which force of impact (peak force and impulse) was calculated. Eighty-six animals were used in this parametric study. The animals were observed for 4 weeks postinjury with two tests of motor recovery (Tarlov score for locomotion and the inclined plane test). After sacrifice at 4 weeks, the spinal cords were removed and, with the use of preset criteria, qualitative histopathological scoring of the extent of tissue damage was carried out. We found that the variable height of weight drop was capable of producing a graded injury that correlated with the force of injury (as measured by the force transducer) and with the outcome parameters of functional recovery and degree of morphological damage in the spinal cord. Histopathologically, there was a tendency to central cavitation of the cord. Both the static load and the dynamic load techniques seem to be valid models of spinal cord injury. Pathologically, however, the tissue damage after static load injury involved primarily the dorsal half of the cord. By contrast, the dynamic load technique produced central cavitation comparable to that observed in human spinal cord injury. In this respect, the dynamic model seems to be superior and its use is therefore recommended for studies of therapeutic intervention for spinal cord injury.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Variable benefits from the use of a number of calcium channel blockers in experimental spinal cord injury have been reported. To our knowledge, these agents have not been previously tested in a contusion model of cord injury in which neurological outcome is one of the critical outcome parameters. We carried out preliminary behavioral toxicity testing to identify a range of low, moderate, and high dosage levels of the calcium channel blocker, nicardipine; these dosage levels were to be used subsequently in formal testing. After laminectomy at T8 under general anesthesia in rats, a 10-g weight was dropped from a height of 5 cm onto the spinal cord. The animals were randomly assigned to four groups: control or one of three nicardipine treatment groups: (a) low dose (1 mg/kg, followed by a continuous 23-hour infusion of 0.5 mg/kg/hour), (b) moderate dose (10 mg/kg, followed by 5 mg/kg/hour for 23 hours, and (c) high dose (20 mg/kg, followed by 23-hour infusion of 10 mg/kg/hour). Functional recovery was tested over the course of 4 weeks with the Tarlov scale, the inclined plane, and a sensory-motor battery of tests (combined behavioral score). After sacrifice at 4 weeks, morphometric analysis of residual gray and white matter was performed at the epicenter of the spinal cord injury. Statistical analysis of the behavioral data failed to reveal any differences among the control or nicardipine treatment groups. The morphometric analysis similarly failed to show differences between the control and any treatment group. (ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

A new subtype of axis fracture, thought to be a variant of the Type II odontoid fracture, is described. High resolution, thin section computed tomography can assist in the identification of comminuted fractures at the base of the dens with associated free fracture fragments. Because these injuries are markedly unstable and cannot be suitably realigned and reduced by external means, early surgical therapy should be considered.

ISSN:0148-396X    

出版商:OVID    

年代:1988

数据来源: OVID