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Biomedical subjects

G Lanzino

Publications and source records attributed to G Lanzino.

At least 73 records · Page 4Linked to original sources
PubMed1996

Gender-related differences in aneurysmal subarachnoid hemorrhage.

Female gender is a recognized risk factor for the occurrence of aneurysmal subarachnoid hemorrhage. In the present study the authors analyzed differences in admission characteristics and outcome between 578 women (64%) and 328 men (36%) who were enrolled in a recently completed clinical trial. The female-to-male ratio was nearly 2:1. The women in the study were older than the men (mean age 51.4 years vs 47.3 years, respectively, p<0.001). Female patients harbored aneurysms of the internal carotid artery more frequently than male patients (36.8% vs. 18.0%, p<0.001) and more often had multiple aneurysms (32.4% vs. 17.6%, p<0.001). On the other hand, anterior cerebral artery aneurysms were more commonly encountered in men (46.1% in men vs. 26.6% in women, p<0.001). Other baseline prognostic factors were balanced between the gender groups. Surgery was performed equally in both sexes (98%), although the time to operation was shorter for women (mean 3.6 days for women vs. 5.3 days for men, p = 0.0002). In the placebo group, the occurrence of vasospasm was not statistically different between the two groups. Primary causes of death and disability were the same, and favorable outcome rates at 3 months were not statistically different between the genders (69.7% for women vs. 73.4% for men, p = 0.243). The odds of a favorable outcome in women versus one in men were not statistically significant either before of after adjustment for age. These observations lead the authors to suggest that although women are older and harbor more aneurysms, the 3-month outcome for women and men who experience aneurysmal subarachnoid hemorrhage is the same.

Adult↗
PubMed1996

Age and outcome after aneurysmal subarachnoid hemorrhage: why do older patients fare worse?

Advanced age is a recognized prognostic indicator of poor outcome after subarachnoid hemorrhage (SAH). The relationship of age to other prognostic factors and outcome was evaluated using data from the multicenter randomized trial of nicardipine in SAH conducted in 21 neurosurgical centers in North America. Among the 906 patients who were studied, five different age groups were considered: 40 years or less, 41 to 50, 51 to 60, 61 to 70, and more than 71 years. Twenty-three percent of the individuals enrolled were older than 60 years of age. Women outnumbered men in all age groups. Level of consciousness (p = 0.0002) and World Federation of Neurological Surgeons grade (p = 0.0001) at admission worsened with advancing age. Age was also related to the presence of a thick subarachnoid clot (p = 0.0001), intraventricular hemorrhage (p = 0.0003), and hydrocephalus (p = 0.0001) on an admission computerized tomography scan. The rebleeding rate increased from 4.5% in the youngest age group to 16.4% in patients more than 70 years of age (p = 0.002). As expected, preexisting medical conditions, such as diabetes (p = 0.028), hypertension (p = 0.0001), and pulmonary (p = 0.0084), myocardial (p = 0.0001), and cerebrovascular diseases (p = 0.0001), were positively associated with age. There were no age-related differences in the day of admission following SAH, timing of the surgery and/or location, and size (small vs. large) of the ruptured aneurysm. During the treatment period, the incidence of severe complications (that is, those complications considered life threatening by the reporting investigator) increased with advancing age, occurring in 28%, 33%, 36%, 40%, and 46% of the patients in each advancing age group, respectively (p = 0.0002). No differences were observed in the reported frequency of surgical complications. No age-related differences were found in the overall incidence of angiographic vasospasm; however, symptomatic vasospasm was more frequently reported in the older age groups (p = 0.01). Overall outcome, assessed using the Glasgow Outcome Scale at 3 months post-SAH, was poorer with advancing age (p < 0.001). Multivariate analysis of overall outcome, adjusting for the different prognostic factors, did not remove the age effect, which suggests that the aging brain has a less optimal response to the initial bleeding. Age as a risk factor is a continuum; however, there seems to be a significant increased risk of poor outcome after the age of 60 years.

Adult↗
PubMed1996

Maturation of intracranial immature teratomas. Report of two cases.

Immature teratomas arising within the central neuraxis are rare neoplasms. These tumors contain diverse cell lineages that retain an embryonal character and display phenotypic differentiation attributed to the three classic germ layers. The clinical management of these lesions is unclear, due in part to their low incidence and to an incomplete understanding of their natural history. Although the potential for phenotypic differentiation and cellular maturation within immature teratomas arising in the gonads is well documented, this has not been described in the intracranial tumors. In the present report, the authors describe two cases of intracranial immature teratomas, one involving the pineal region and the other involving the left frontotemporal lobes, which underwent cellular differentiation and maturation. At initial resection, the tumors from both cases were composed predominantly of primitive neuroepithelial tissue that was admixed with immature and differentiating mesenchymal and epithelial structures. No foci of germinoma, endodermal sinus, choriocarcinoma, or embryonal carcinoma tissue were present. Subsequent resections in both cases revealed an absence of immature tissue. The tumor in Case 1 contained only differentiated epithelial and mesenchymal tissue with no neuroepithelial component, whereas the tumor in Case 2 demonstrated abundant mature neuronal and glial tissue. These two cases from different intracranial sites suggest that spontaneous maturation may be a significant aspect of the natural history of intracranial immature teratomas.

Brain Neoplasms↗
PubMed1995

1995 AUR Memorial Award. Gamma knife irradiation-induced changes in the normal rat brain studied with 1H magnetic resonance spectroscopy and imaging.

RATIONALE AND OBJECTIVES: The pathogenesis of brain injury following radiosurgery is poorly understood. To better elucidate the relationship between blood-brain barrier disruption and metabolic derangements, we used magnetic resonance (MR) imaging and 1H MR spectroscopy to detect early changes from focused single-fraction, high-dose irradiation injury in rat brains. METHODS: Using the Leksell gamma knife, we irradiated the frontoparietal cortex of 11 male Wistar rats with a single dose of 120 Gy. Four weeks later, we sequentially performed water-suppressed 1H MR spectroscopy and gadopentetate dimeglumine-enhanced T1-weighted MR imaging. Metabolic maps were created of n-acetylaspartate (NAA), creatine and choline (Cr/Cho), and lactate from the MR spectroscopy data set. Detection of irradiation injury among the tested modalities was assessed by receiver operating characteristic analysis and by quantitative signal intensity changes. Pathologic confirmation of irradiation damage was obtained in all rats. RESULTS: Gadopentetate dimeglumine-enhanced T1-weighted MR imaging was the only imaging modality that detected statistically significant signal intensity changes (p < .05). No reproducible changes in the metabolites of interest could be detected by 1H MR spectroscopy. CONCLUSION: In our animal model, blood-brain barrier disruption was a reproducible, integral finding of single-fraction, high-dose irradiation injury. No reproducible metabolic derangements of ischemia or necrosis were detected by 1H MR spectroscopy, possibly because of dose-latency effects or sensitivity issues.

Animals↗
PubMed1995

Microvascular decompression for glossopharyngeal neuralgia.

Glossopharyngeal neuralgia is an uncommon cause of facial pain with a relative frequency of 0.2 to 1.3% when compared with trigeminal neuralgia. It is characterized by intermittent, lancinating pain involving the posterior tongue and pharynx, often with radiation to deep ear structures. Since its first description in 1910 by Weisenburg, a variety of destructive procedures have been performed to provide relief in patients whose pain was refractory to medical treatment. These procedures all necessitated the sacrifice of the glossopharyngeal nerve and, in most cases, also involved the destruction of at least part of the vagus nerve as well. In 1977, Laha and Jannetta reported good results in four patients who underwent microvascular decompression of the glossopharyngeal and vagus nerves for glossopharyngeal neuralgia. Since 1971, 40 patients have undergone microvascular decompression of the glossopharyngeal and vagus nerves for treatment of typical glossopharyngeal neuralgia. This procedure provided excellent immediate results (complete or > 95% relief of pain) in 79%, with an additional 10% having a substantial (> 50%) reduction in pain. Long-term follow-up (mean, 48 mo; range, 6-170 mo) reveals excellent results (complete or > 95% reduction in pain without any medication) in 76% of the patients and substantial improvement in an additional 16%. There were two deaths at surgery (5%) both occurring early in the series as the result of hemodynamic lability causing intracranial hemorrhage. Three patients (8%) suffered permanent 9th nerve palsy. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Calcium-activated proteolysis in rat neocortex induced by transient focal ischemia.

Ischemia-induced elevation of intracellular calcium triggers a cascade of events which is considered to play a major role in neuronal death. One candidate to participate in this process is the calcium-sensitive protease, calpain. This protease is activated by calcium, and is capable of degrading critical cytoskeletal and regulatory proteins. In order to further elucidate the role of calpain in focal ischemic damage, the present study investigated the proteolysis of spectrin, a preferred substrate for calpain, in response to transient focal ischemia. Ischemia was induced by occluding reversibly both carotid arteries and the left middle cerebral artery for three hours in Sprague-Dawley rats. Western blotting techniques were used to identify and quantify the amounts of spectrin breakdown products (BDPs) in neocortical samples from the area destined for infarction, the peri-infarct area, and the contralateral hemisphere. Substantial increases in spectrin proteolysis were observed within the first few hours of ischemia in the areas that will undergo infarction. The increase in spectrin BDPs in these areas reached a plateau around the end of the 3 h ischemic period. In the peri-infarct zone, the levels of spectrin BDPs increased in a biphasic manner. A small to moderate increase was observed by the second hour of ischemia, followed by a larger increase between the 6th and 24th hours post-ischemia. The contralateral neocortex showed a significant increase in BDPs at 2 h after the initiation of ischemia. A smaller increase in BDPs was observed thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Angiographic characteristics of dural arteriovenous malformations that present with intracranial hemorrhage.

Dural arteriovenous malformations (dAVMs) are uncommon lesions that constitute about 12% of all the arteriovenous malformations. Depending on the location and the hemodynamics of the lesion, bruit, focal neurological deficit, and visual symptoms represent the more common presentation modalities. Although uncommon, intracranial hemorrhage can occur. In the present study, we report six patients with dural arteriovenous malformation that presented with intracranial hemorrhage. In five cases the hemorrhage was intraparenchymal (localized to the parietooccipital area in three), while it was confined to the subarachnoid space in the remaining one. The dAVM involved the transverse sinus in three cases, was based along the tentorial incisura in two, and was at the level of the torcular Herophili in one. Leptomeningeal drainage was present in all the cases. Aneurysmal dilatation of the draining vein(s) was identified in three. Sinus stenosis/occlusion was identified in two of the four patients with a dAVM draining into a major dural sinus. Four patients underwent pre-operative embolization, and all patients had surgical resection of their lesions. Anatomical cure, as defined by absence of any residual dAVM on postoperative angiogram, was achieved in all six patients. We conclude that several findings such as leptomeningeal drainage, location outside a major venous sinus, variceal dilatation, sinus stenosis/occlusion increase the risk of bleeding and are frequently observed in those dAVMs that present with intracranial hemorrhage. Recognition of these angiographic features is critical in planning a therapeutic approach tailored to the characteristics of the individual case. When these angiographic findings are present, prompt and definitive treatment is mandatory.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Arteriovenous malformations that rupture during pregnancy: a management dilemma.

Intracranial haemorrhage due to rupture of an arteriovenous malformation (AVM) during pregnancy is a rare but serious condition that warrants prompt recognition. Once the diagnosis is made, the management is primarily based on neurosurgical rather than obstetric considerations. Due to its rarity, no definitive guidelines exist, and the best time to perform elective surgery (i.e., at presentation or at completion of the pregnancy) is ill-defined. This report describes three patients recently treated at our institution who had AVMs that ruptured during pregnancy. These cases well summarize the difficulties encountered in treating such patients. The diagnostic as well as the therapeutic implications of this condition are discussed.

Adolescent↗
PubMed1994

Electrocardiographic abnormalities after nontraumatic subarachnoid hemorrhage.

Electrocardiographic (ECG) abnormalities and rhythm disorders are frequently observed in the acute phase after spontaneous subarachnoid hemorrhage (SAH). These abnormalities are benign and transient in most cases; however, in some patients they can take the form of life-threatening arrhythmias such as ventricular flutter/fibrillation and torsade de pointe. Among the ECG abnormalities observed, prolongation of the Q-T interval, especially if associated with hypokalemia, deserves particular attention because it is frequently present in those patients who will develop life-threatening ventricular arrhythmias. In some cases, the ECG abnormalities mimic those observed in the setting of acute myocardial infarction. Elevated creatine phosphokinase-myocardial fraction isoenzyme, suggesting underlying cardiac damage, has also been reported. The pathophysiology of these abnormalities is related to an imbalance of autonomic cardiovascular control. Because some electrical and morphological heart abnormalities are experimentally induced by catecholamine injection, the role of circulating catecholamines has been investigated in depth. Pathologically, the hearts of patients who die after SAH can show a peculiar morphological lesion defined as "myocytolysis." Intramyocardial hemorrhages have also been described. These observations confirm the utility of continuous cardiac monitoring in patients with SAH.

Acute Disease↗
PubMed1994

Neuroprotection with a calpain inhibitor in a model of focal cerebral ischemia.

BACKGROUND AND PURPOSE: Excessive elevation of intracellular calcium and uncontrolled activation of calcium-sensitive events are believed to play a central role in ischemic neuronal damage. Calcium-activated proteolysis by calpain is a candidate to participate in this form of pathology because it is activated under ischemic conditions and its activation results in the degradation of crucial cytoskeletal and regulatory proteins. The present studies examined the effects of a cell-penetrating inhibitor of calpain on the pathological outcome after transient focal ischemia in the brain. METHODS: Twenty-five male Sprague-Dawley rats were divided into four groups: a saline-treated group, a vehicle-treated group, and two calpain inhibitor-treated groups (Cbz-Val-Phe-H; 30-mg/kg and 60-mg/kg cumulative doses). Ischemia was induced by occluding the left middle cerebral artery and both common carotid arteries for 3 hours followed by reperfusion. Animals were killed 72 hours after surgery, and quantitative measurements of infarction volumes were performed using histological techniques. Eight additional rats were killed 30 minutes after ischemia and examined for the extent of proteolysis using immunoblot techniques. A final group of 12 animals was decapitated after injection of vehicle or calpain inhibitor, and the proteolytic response was measured after 60 minutes of total ischemia. RESULTS: Rats treated with Cbz-Val-Phe-H exhibited significantly smaller volumes of cerebral infarction than saline-treated or vehicle-treated control animals. Intravenous injections of cumulative doses of 30 mg/kg or 60 mg/kg of Cbz-Val-Phe-H were effective in reducing infarction, edema, and calcium-activated proteolysis. The proteolytic response to postdecapitation ischemia was also reduced by the calpain inhibitor. CONCLUSIONS: These results demonstrate the neuroprotective effect of a cell-penetrating calpain inhibitor when administered systemically. The findings suggest that targeting intracellular, calcium-activated mechanisms, such as proteolysis, represents a viable therapeutic strategy for limiting neurological damage after ischemia.

Analysis of Variance↗
PubMed1993

Selective loss of NADPH-diaphorase-containing neurons in the dentate gyrus following transient ischemia.

The effect of transient forebrain ischemia on NADPH-diaphorase-containing neurons was examined in the dentate gyrus of the gerbil. NADPH-diaphorase histochemistry was performed in animals subjected to temporary occlusion of the common carotid arteries and sham-operated animals. Seven days following transient ischemia, the number of NADPH-diaphorase-positive neurons in the infragranular zone of the dentate gyrus was reduced by approximately 50% compared with control animals. Since neighboring granule cells are known to be resistant to this level of ischemic challenge, the present observations indicate that NADPH-diaphorase-containing neurons in the dentate gyrus are selectively vulnerable to brief ischemia.

Amino Acid Oxidoreductases↗
PubMed1993

Vertebro-basilar aneurysms: does delayed surgery represent the best surgical strategy?

The appropriate time to perform surgery for posterior circulation aneurysms is debated. Controversy exists secondary to the lack of information regarding the overall management and outcome, as well as difficulties with their surgical treatment and infrequent occurrence. The present study examines the results of 46 patients with ruptured vertebro-basilar aneurysms treated with a delayed surgical protocol. Twenty-four were Hunt-Hess grade I/II on admission, 13 were grade III, and 9 grade IV/V. Nineteen patients (40%) (4 grade I/II, 6 grade III, and the 9 grade IV/V on admission) died before meeting the required conditions for surgery. Causes of death were vasospasm (8 cases), direct effect of the initial bleeding (7 cases), and rebleeding (4 cases). Surgical results were excellent/good in 87% of the patients. Surgical mortality was 8% (2 out of 24). In this study, despite encouraging surgical results, overall mortality was disappointingly high. We suggest that as more experience is gained in treating vertebrobasilar aneurysms, early surgery should be performed in selected cases. Early surgery is prophylactic for rebleeding and allows for more aggressive treatment of cerebral vasospasm.

Adult↗
PubMed1993

Orbital pain and unruptured carotid-posterior communicating artery aneurysms: the role of sensory fibers of the third cranial nerve.

Intact aneurysms of the carotid siphon at the point of take-off of the posterior communicating artery may exhibit orbital pain, whether associated with oculomotor palsy or not as a warning symptom prior to rupture. In order to explain this symptom the hypothesis of a sensory pathway within the third cranial nerve, which is liable to compression by the enlarging aneurysm sac, has been investigated. Data from human autopsy material show evidence of sensory ganglion cells within the rootlets of the oculomotor nerve; furthermore, studies in animals prove that the third nerve contains sensory fibers which run proximally along the nerve bundles, enter the brainstem and reach the spinal trigeminal nucleus. These fibers come from the ophthalmic division of the fifth nerve and join the third nerve at the level of the lateral wall of the cavernous sinus. Although a number of questions remain to be solved, the presence of a sensory pattern within the third nerve could account for fronto-orbital pain from enlarging aneurysms impinging on the third nerve itself.

Animals↗
PubMed1993

Chordomas and chondrosarcomas involving the cavernous sinus: review of surgical treatment and outcome in 31 patients.

During the last 9 years, 31 patients with chordomas (20 cases) and chondrosarcomas (11 cases) involving the cavernous sinus have been treated using an aggressive surgical approach. On the basis of postoperative magnetic resonance imaging (MRI), 17 patients were considered to have undergone total removal, whereas in the remaining 14 cases the tumor was either subtotally or partially removed. Surgical complications were most commonly encountered among patients who had undergone previous operations. One patient died 3 months after the operation as a result of pulmonary embolism. Significant disability occurred in one patient because of thalamic perforator occlusion and hemorrhage. Recovery of extraocular muscle function was gratifying, and correlated to the preoperative functional level. After a median follow-up of 24 months, three recurrences (21%) occurred among the 14 patients who had undergone incomplete removal. No recurrence was observed among the 17 patients with total resection. This experience shows that gross radical removal of chordomas and chondrosarcomas involving the cavernous sinus can be accomplished with an acceptable surgical morbidity. However, much longer follow-up will be required to determine whether such aggressive surgical treatment results in cure or long-term control of these neoplasms.

Adolescent↗
PubMed1993

Paraseller meningiomas: incidence of involvement of extracavernous structures as determined by magnetic resonance and computed tomography.

Parasellar meningiomas frequently extend beyond the cavernous sinus into adjacent structures. In order to determine the incidence of involvement of adjacent sites, we retrospectively evaluated the computed tomography and nuclear magnetic resonance scans of 65 consecutive patients with meningiomas invading the cavernous sinus. Thirteen nearby anatomic sites were analyzed for tumor involvement. The sites most frequently involved were the lateral sphenoid sinus wall (93%), the ipsilateral petrous apex (70%), the ipsilateral posterior petrous bone surface (59%), the sella (59%), the intracranial clival surface (44%), and the suprasellar cistern (41%). The sella, clival bone marrow, orbital apex, pterygopalatine fossa, and prestyloid parapharyngeal space were more commonly involved in recurrent tumors. Lesions were also subdivided into five groups according to whether or not they involved only one part of the cavernous sinus (grade 1), two parts of the cavernous sinus (grade 2), surrounded the cavernous carotid artery (grade 3), surrounded and narrowed the cavernous carotid artery (grade 4), or involved both sides of the cavernous sinus (grade 5). Among the 63 cases that could be assigned to a category, seven were grade 1 lesions, 13 were grade 2, 13 were grade 3, 16 were grade 4, and 14 were grade 5. Tumor grade is helpful in predicting the difficulty of resection of the cavernous component of the tumor. The incidence of involvement of adjacent sites is also helpful in assessment of imaging studies and in planning the most appropriate surgical approach.

Journal Article↗