Rapid improvement of diffusion-weighted imaging abnormalities after glucose infusion in hypoglycaemic coma.

Diffusion-weighted imaging (DWI) may detect hyperintense lesions in patients with transient hypoglycaemia-induced hemiparesis or coma, which are completely reversible after glucose infusion.1(-)3 In vivo animal studies have documented the visualisation of such hypoglycaemia-induced changes of signal intensity and the reversal by glucose intake in detail.4 However, the time necessary for hyperintense lesions on DWI to disappear after glucose infusion in humans is still unclear. A 54 year old woman presented comatose with brain stem signs and severe hypoglycaemia. DWI demonstrated hyperintense lesions in the corpus callosum and internal capsules. She was treated with IV glucose. These lesions had resolved significantly on imaging 2 hours later and completely resolved on repeat imaging 2 days later. This report documents the time course of recovery of neurological lesions induced by hypoglycaemia after treatment with IV glucose.

Simultaneous multi-section perfusion CT and CT angiography for the assessment of acute ischemic stroke.

BACKGROUND: Introduction of helical computed tomography (CT) scanning has enabled rapid imaging of the vascular status by means of CT angiography and perfusion CT. By virtue of recent multi-detector technology, helical CT has the ability to perform both CT angiography and multi-section perfusion CT simultaneously. This study investigated the clinical feasibility of simultaneous assessment of perfusion CT and CT angiography in patients with acute ischemic stroke. METHOD: Perfusion CT and CT angiography were performed simultaneously in a series of consecutive 31 acute ischemic stroke patients. The time required for the entire processing was about 15 minutes. Contrast agent was used in a total dose of 100 ml (35 ml for perfusion CT and 65 ml for CT angiography). FINDINGS: Simultaneous perfusion CT scans and CT angiographies were of diagnostic quality for 29 patients (94%). In large territorial infarct patients, perfusion CT could predict all perfusion deficits of the final lesions (10 out of 10 lesions) and CT angiography could detect 9 of 10 occlusions of major cerebral arteries (90%). In patients with small lacunar or subcortical infarcts, perfusion CT could predict 9 out of 19 lesions (47.4%), and false-negative were encountered in small lesions (three patients) or in inadequate coverage of data acquisition (seven patients). Acute stage thrombolytic intervention could be carried out based on the findings, and the success of thrombolytic therapy could be demonstrated by follow-up study. CONCLUSIONS: Simultaneous perfusion CT and CT angiography is the very useful tool for the rapid and adequate diagnosis of almost all of the large territorial infarcts and some of non-territorial lacunar infarcts. It is an easy-to-perform and safe imaging technique to assess acute ischemic stroke.

Differential regulation of intracellular Ca2+ signalling induced by high K+ and endothelin-1 in single smooth muscle cells of intact canine basilar artery: detection by means of confocal laser microscopy.

Changes in intracellular calcium concentration ([Ca2+]i) in smooth muscle cells play the key role in regulation of vascular smooth muscle tone and pathogenesis of cerebral vasospasm. In this study, we adopted the confocal laser microscopy to detect the fluorescence signals arising from the individual smooth muscle cells of canine basilar artery. Ring preparations were made, loaded with fluo-3 and changes in fluorescence induced by high K+ and endothelin-1 (ET-1) were measured by confocal laser microscopy. In some unstimulated smooth muscle cells Ca2+ waves arising from discrete region of the cell propagated to the whole cell with a velocity of approximately 10 microm/s. High K+ (80 mmol/L) induced a rapid rise in [Ca2+]i, the peak level being consistently reached approximately 10 s after stimulation. In contrast, the time to peak level of [Ca2+]i induced by ET-1 (0.3 micromol/L) varied widely between 13 and 26 s among individual cells, an indication that the extent of nonuniform coordination of increases in [Ca2+]i in individual cells may be partly responsible for the different time courses of tension development of vascular smooth muscle in response to the vasoactive stimulants. The increase in [Ca2+]i induced by ET-1 was transient but a pronounced and sustained contraction developed further in response to ET-1. Thus ET-1 has a biological property as a potential candidate to elicit cerebral vasospasm. Confocal laser microscopy could be a useful tool to measure the changes in [Ca2+]i in individual smooth muscle cells of cerebral artery.

Endothelin: receptor subtypes, signal transduction, regulation of Ca2+ transients and contractility in rabbit ventricular myocardium.

Endothelin (ET) isopeptides, ET-1, ET-2 and ET-3, elicit a positive inotropic effect (PIE) in association with a negative lusitropic effect, essentially with identical efficacies and potencies in the isolated rabbit papillary muscle, but with different concentration-dependent properties. Pharmacological analysis indicates that the PIE of ET-1 is mediated by an ETA2 subtype that is less sensitive to BQ-123 and FR139317, whereas the PIE of ET-3 is mediated by an ETA1 subtype that is highly sensitive to these ETA antagonists. ETs increased the amplitude of intracellular Ca2+ transient (CaT) in indo-1 loaded rabbit ventricular myocytes, but the increase was much smaller than that produced by elevation of [Ca2+]o or isoproterenol for a given extent of PIE, an indication of increased myofibrillar Ca2+ sensitivity. ETs stimulate phosphoinositide (PI) hydrolysis, which leads to production of inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Evidence for the role of IP3-induced Ca2+ release in cardiac E-C coupling is tenuous. Generation of IP3 induced by ET-1 was transient and returned to the baseline level when the PIE reached an elevated steady level. Protein kinase C (PKC) that is activated by DAG and also via other pathways triggered by ETs stimulates Na+-H+ exchanger to lead to an increased [Na+]i and alkalinization. The former may contribute to an increase in the amplitude of CaT through Na+-Ca2+ exchanger, and the latter, to an increase in myofibrillar Ca2+ sensitivity. A number of PKC inhibitors, such as staurosporine, H-7, calphostin C and chelerythrine, consistently and selectively inhibited the PIE of ET-3 without affecting the PIE of isoproterenol and Bay k 8644. The maximum inhibition was 20-30% of the total response. A Na+-H+ exchange inhibitor, [5-(N-ethyl-N-isopropyl) amiloride (EIPA)] or a Ca2+ antagonist, verapamil, could not completely inhibit the PIE of ET-3, but the combination of both inhibitors totally abolished the PIE of ET-3. These findings indicate that activation of PKC and subsequent activation of Na+-H+ exchanger and/or L-type Ca2+ channels may play a crucial role in the cardiac action of ET isopeptides in the rabbit ventricular myocardium.

[Localized glioma in the occipital lobe manifesting as scintillating scotoma: case report].

An 11-year-old female presented with headache in May 1993. Magnetic resonance (MR) imaging disclosed a small lesion (9 mm in diameter) in the left occipital lobe. No treatment was performed because the lesion was small. She subsequently developed frequent episodes of scintillating scotoma in the right visual field eleven months later. MR imaging eleven months after the first MR imaging showed the lesion had enlarged to 14 mm in diameter. Preoperative surface electroencephalography (EEG) detected no spike waves. The diagnosis was localized glioma. The mass was totally removed by gyrectomy in December 1994. Intraoperative cortical EEG demonstrated spike waves which disappeared after tumor removal. The histological diagnosis was pleomorphic xanthoastrocytoma. No postoperative neurological deficit was recognized, and scintillating scotoma and headache disappeared. Postoperative stereotactic radiosurgery was performed. The scintillating scotoma was caused by the tumor, because the spike wave and phase reversal were detected by the intraoperative cortical EEG. Intraoperative EEG is useful for the diagnosis of epilepsy caused by tumor. Sulcotomy and gyrectomy are the optimal surgical treatments for epilepsy caused by a localized glioma.

[A case of mycotic ICA petrous portion aneurysm treated with endovascular surgery].

A case is reported of mycotic aneurysm at the petrous portion of the internal carotid artery (ICA) treated with an endovascular procedure. A sixty-seven-year-old male who had suffered from chronic otitis media bilaterally for the last five years showed a sudden onset of massive left otorrhagia. Cerebral angiogram at the eighth day of otorrhagia disclosed a big aneurysm at the petrous portion of the left ICA. The aneurysm was round in shape but its wall was irregular. The angiogram also showed that a stenotic finding of the left ICA just at the proximal portion of the aneurysm and the neck of the aneurysm was not broad. Bone window computed tomography showed a destroyed petrous bone around the left ICA. The results of the Matas test and the Allcock test told us that left ICA occlusion should not be selected as a treatment. We decided that endovascular surgery could be applied as the treatment of this pathology. An endovascular procedure was performed for this pathology one month after the otorrhagia. The aneurysm was successfully embolized using platinum coils beside a part of the neck without occlusion of the parent artery. The patient's postoperative course was not eventful. We concluded that endovascular surgery might be the first choice for the treatment of an ICA petrous portion mycotic aneurysm.

[A case of multiple cerebral mycotic aneurysms treated with endovascular surgery].

A case of multiple mycotic cerebral aneurysms successfully treated with endovascular surgery is reported. A nine-year-old boy who has suffered from hypertrophic obstructive cardiomyopathy and active infectious endocarditis in the mitral valve developed sudden consciousness disturbance and convulsion. Computerized tomography revealed subarachnoid hemorrhage with subcortical hematoma in the left parietal lobe. Angiography demonstrated four aneurysms at the distal part of the middle cerebral artery on both sides. Since his physical status had been deteriorating, it was difficult to undergo a usual surgical operation. Therefore, endovascular surgery was performed. The catheter was super-selectively advanced to the parent artery of the left posterior parietal artery aneurysm which seemed to be the hemorrhagic source, and the embolization was performed using platinum coils and liquid embolization material. Angiography after embolization showed that the aneurysms had been successfully occupied by the materials while the aneurysm of the right anterior parietal artery had not responded antibiotic therapy. Therefore the second embolization was carried out to the parent artery of the aneurysm of the right anterior parietal artery one month later. The patient had no neurological deficit after embolization and no aneurysms have been detected by the follow-up angiogram after the second embolization. An endovascular approach might be an alternative useful treatment for cases in which the patient has, deteriorated so much that it is considered difficult to perform open craniotomy under general anesthesia.