Nitric oxide does not play a major role in the regulation of systemic hemodynamic responses to acute normovolemic hemodilution

Background: The mechanisms of cardiovascular changes following acute normovolemic hemodilution (ANH) have not been fully elucidated. We tested the hypothesis that inhibition of nitric oxide synthesis attenuates ANH-induced cardiovascular responses.
Methods: We observed the effects of N^ω-nitro-L-arginine methyl ester (L-NAME) pretreatment on ANH-induced cardiovascular responses and compared these effects with those elicited by phenylephrine (PHE). Twenty dogs anesthetized with isoflurane were divided into two groups: one group was pretreated with L-NAME and the other with PHE. Both groups were normovolemically hemodiluted using 6% hydroxyethyl starch to reduce the hemoglobin concentration to approximately 50% of the pretreatment value.
Results: Pretreatment with either L-NAME or PHE caused a significant increase in mean aortic blood pressure (MAP) and systemic vascular resistance (SVR) with a significant decrease in cardiac output (CO) and stroke volume (SV). However, no remarkable differences in these variables were seen between groups. In both groups ANH produced increases in heart rate, CO, SV, and maximal left ventricular dP/dt with a significant decrease in SVR. No significant differences in these variables were apparent after ANH except that MAP was decreased in the PHE group but not in the L-NAME group.
Conclusion: Our results suggest that nitric oxide does not play a major role in mediation or modulation of the systemic vascular responses to ANH.     

Influence of opioids on the vascular tone of isolated porcine coronary artery segments

BACKGROUND: It was the aim of this study to elucidate the influence of opioids on coronary vascular tone using the model of isolated porcine coronary artery segments. METHODs: We studied the effects of fentanyl (0.01, 0.1, 1.0 microg ml(-1)), alfentanil (0.1, 1.0, 10 microg ml(-1)), and sufentanil (0.01, 0.1, 1.0 microg ml(-1)) on the contractile response to three vasoconstrictors, acetylcholine, histamine and serotonin. RESULTS: Fentanyl (0.1, 1.0 microg x ml(-1)) dose-dependently attenuated the contractile response to acetylcholine, but not to histamine and serotonin. There were no differences in fentanyl's vasorelaxing potency between rings with intact and denuded endothelium. Alfentanil and sufentanil did not exert any significant influence on any of the vasoconstrictors tested. CONCLUSION: It is concluded that, in isolated porcine coronary artery rings, fentanyl at high concentrations has an attenuating effect on acetylcholine-induced contractions, which is independent of endothelial function, whereas alfentanil and sufentanil do not influence coronary vascular tone.     

Does halothane or isoflurane affect hypoxic and post‐hypoxic vascular response in rabbit aorta?

BACKGROUND: Halothane and isoflurane affect differently endothelium-dependent and -independent vasorelaxation at 95% O2. In addition, hypoxic vascular response might involve endothelium-dependent and -independent mechanisms. Therefore, we investigated, in rabbit aortic rings, 1) the influence of halothane and isoflurane on vasodilation at 95% O2 and on hypoxic-induced vasorelaxation at 0% O2 and 2) the influence of halothane and isoflurane on endothelium-dependent and -independent post-hypoxic vascular response. METHODS: Endothelium-intact and endothelium-denuded rabbit aortic rings were used. Phenylephrine precontracted rings were exposed, at 95% O2, to acetylcholine (ACh, 10(-9) to 10(-4) M) or sodium nitroprusside (SNP, 10(-9) to 10(-4) M) in the presence or absence of anaesthetic at 1 or 2 MAC. Precontracted rings were also exposed to an acute reduction in O2 from 95% to 0% followed by an acute reoxygenation with 95% O2 in the absence or presence of anaesthetic at 1 or 2 MAC. RESULTS: At 95% O2, halothane decreased endothelium-dependent relaxation to ACh, while endothelium-independent relaxation to SNP was decreased only at 2 MAC. Isoflurane did not modify ACh- or SNP-induced relaxation. At 0% O2, neither halothane nor isoflurane altered the hypoxic vascular relaxation. Post-hypoxic response was not changed either. CONCLUSION: Our results indicate that halothane and isoflurane do not alter vascular hypoxic response in conductance arteries.     

Efficacy of targeted CT angiography in evaluation of intracranial internal carotid artery disease

RATIONALE AND OBJECTIVES: This study evaluated the efficacy of targeted computed tomographic (CT) angiography in the diagnosis of intracranial internal carotid artery (ICA) disease and compared the results of routine and targeted CT angiography. MATERIALS AND METHODS: Fifty-four patients (24 male and 30 female patients aged 2 months to 87 years) were examined with CT angiography. Digital subtraction angiography (DSA) was performed in 42. CT angiograms were reconstructed with the maximum-intensity projection (MIP) algorithm. Targeted CT angiography was performed by individually reconstructing a single ICA territory. Each ICA was divided into four segments, and findings of routine MIP CT angiography, routine MIP plus targeted CT angiography, and DSA were reviewed independently by two neuroradiologists for vascular lesions involving each segment. Routine and targeted CT angiograms were also evaluated to determine how well both ICAs were visualized. RESULTS: Routine CT angiography was rated good or excellent for ICA visualization in 64% of cases, compared with 81% for targeted CT angiography (P = .0005). The overall agreement between routine CT angiography and DSA and between routine plus targeted CT angiography and DSA was 92% and 94%, respectively. There was no statistically significant difference between the percentages of vascular lesions detected with routine CT angiography alone and with routine plus targeted CT angiography. Both methods tended to show false-positive findings of steno-occlusive disease, but targeted CT angiography showed details of aneurysms and stenotic lesions that were easily overlooked with routine CT angiography alone. CONCLUSION: Routine plus targeted CT angiography, while providing superior image quality, did not have much clinical effect; further assessment may be needed.     

Proliferation, Vascular Endothelial Growth Factor Expression and Cavernous Sinus Invasion in Growth Hormone Secreting Pituitary Adenomas

Summary  Surgical cure of growth hormone producing pituitary adenomas (GHomas) becomes difficult when they invade the cavernous sinus (CS). Tumour proliferative activity and angiogenesis are thought to be required for tumour growth and invasion, and vascular endothelial growth factor (VEGF) activates neovascularization around tumours. In this study, the mechanism and clinical significance of CS invasion is analysed. In 25 surgically treated GHomas, the extent of CS invasion was classified as high (Knosp's grade 3 and 4), and low (grade 0, 1 and 2) MR grades, and the MR grades were compared with tumour proliferative potential (Ki-67 expression), angiogenetic demand (VEGF expression), volume of adenomas and serum hormone levels.  The Ki-67 index of high MR grade adenomas (1.17±0.62%) was significantly higher than that of low MR grade adenomas (0.55±0.42%, p=0.027), whereas VEGF expression showed no significant correlation with MR grades (p>0.999). Tumour volume also showed a significant correlation with MR grade (p=0.002). VEGF expression was not correlated with serum hormone level and volume, but was correlated with tumour proliferative potential. Proliferative potential and tumour volume were two independent factors related to CS invasion. Although VEGF expression was not a direct factor related to CS invasion, it may indirectly play a role in activation of tumour aggressiveness, which is required in CS invasion.  Our results show that high MR grade adenomas have higher proliferative ability. In order to improve the surgical outcome, pre-operative medical debulking is indicated, particularly, in such adenomas.     

Multifocal Cerebral Hemangio-Endothelioma. Case Report and Review of the Literature

BACKGROUND: Intracranial hemangio-endotheliomas (HE) are rare vascular tumours that present histological features and biological behaviour of an intermediate malignancy. We report the first case of primary HE presenting as multiple intracranial masses. CASE DESCRIPTION: The patient is a 20-year-old female who presented with paresis of the left arm. Magnetic Resonance imaging (MRI) showed multiple lesions in both frontal lobes. Total surgical excision of the tumours was obtained; a histological diagnosis of hemangio-endothelioma was made. Five months later, MRI scan showed new intradiploic skull lesions whereas a scintigraphic study revealed multicentric extracranial bone involvement. Treatment based on interferon-alpha (IFN-alpha) administration was undertaken; this produced partial regression of the lesions. Approximately three years after the first operation, the patient is in good clinical condition. CONCLUSIONS: Surgery continues to play the leading role in the treatment of intracranial HE. However, adjuvant therapy with IFN represents a new and well-tolerated therapeutic method for residual intracranial lesions as well as multicentric extracranial disease.     

Statistical Analysis of Factors Affecting the Outcome of Patients with Ruptured Distal Anterior Cerebral Artery Aneurysms

Summary  The clinical factors affecting the outcome of patients with ruptured distal anterior cerebral artery (ACA) aneurysms were analyzed using multiple logistic regression analysis.  The medical records were reviewed of 52 patients (57 aneurysms) with ruptured distal ACA aneurysms operated on by the same neurosurgeon over 25 years. The standard policy was early surgery for patients in Hunt and Kosnik grades I to IV. Age, sex, Hunt and Kosnik grade, timing of operation, size of aneurysms, number of aneurysms, association of intracerebral haemorrhage (ICH), intraventricular haemorrhage, and azygos ACA, use of temporary clipping , occurrence of premature rupture, and presence of psychiatric change were investigated. Univariant analysis disclosed that clinical grade (P=0.0006), size of aneurysm (P=0.005), and size of ICH (P=0.012) affected the outcome of patients. Multiple logistic regression analysis found that Hunt and Kosnik grade (P=0.010) and timing of operation (P=0.033) affected the outcome. There was no significant relationship between long-term outcome and clinical factors, although a close relationship was found with Hunt and Kosnik grade (P=0.071).  Clinical grade and timing of the operation affected the outcome of patients with ruptured distal ACA aneurysms. Patients harboring ICH of over 3 cm diameter in poor grades should also be carefully treated.     

Animal Model for Cerebral Arteriovenous Malformation

Summary  Background. The present study was conducted to establish an animal model for the investigation of the pathophysiology and haemodynamics of cerebral arteriovenous malformation (AVM) but also to assess therapeutic aspects.  Method. For anatomic and haemodynamic reasons, dogs were chosen as the animal model. An arteriovenous fistula was created by interposing a segment of the superficial temporal artery between one of the main branches of the middle cerebral artery and the dorsal sagittal sinus. A temporal muscle graft supplied by this artery was implanted intracerebrally in the ischaemic area.  Findings. The angiographic and histopathologic findings obtained in the animal model are comparable with the situation found in intracerebral AVM in humans.  Interpretation. The animal model of intracerebral AVM established in this study allows for further investigation of the pathophysiology and dynamics of this disorder. It may help to develop better therapeutic options and thus improve the prognosis of affected patients.     

常见几种疾病的血液流变学指标的观察与分析

[目的 ]　探讨血液流变学指标在临床常见疾病中的应用价值。　 [方法 ]　对 2 91例 5种疾病患者血液进行血液流变学指标测定 ,并与 10 0名体检健康者血液作比较分析。　 [结果 ]　临床常见的脑梗死 ,冠状动脉粥样硬化 ,急、慢性支气管炎 ,糖尿病等疾病的血液流变学指标都存在异常变化。　 [结论 ]　临床上可通过血液流变学指标的检查来帮助预防、诊断和治疗这些病     

急性颅脑损伤脑疝51例临床分析

目的:探讨急性颅脑损伤脑疝的临床特点及各种影响预后的因素,以提高急性颅脑损伤脑疝的诊断和治疗水平,降 低其病死率.方法:对 2000～ 2003年收治的 51例急性颅脑损伤合并脑疝患者的临床资料进行回顾性分析.结果: 收治的急性颅脑损伤合并脑疝患者 51例通过手术或非手术治疗方法,死亡 33例,住院病人病死率高达 64.7%.主要 死亡原因:颅内血肿及脑挫裂伤后脑水肿引起的 ICP增高形成脑疝和原发性或继发性脑干伤;其次是各种严重的并 发症.结论:急性颅脑损伤引起脑疝伤残、病死率极高,其预后与 GCS计分、瞳孔变化、损伤类型、年龄大小、手术时 机及手术指征的掌握密切相关.