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Ayumi Nishida

Publications and source records attributed to Ayumi Nishida.

6 recordsLinked to original sources
PubMed2005

Enhanced brain angiogenesis in chronic cerebral hypoperfusion after administration of plasmid human vascular endothelial growth factor in combination with indirect vasoreconstructive surgery.

OBJECT: Vascular endothelial growth factor (VEGF) is a secreted mitogen associated with angiogenesis. The conceptual basis for therapeutic angiogenesis after plasmid human VEGF gene (phVEGF) transfer has been established in patients presenting with limb ischemia and myocardial infarction. The authors hypothesized that overexpression of VEGF using a gene transfer method combined with indirect vasoreconstruction might induce effective brain angiogenesis in chronic cerebral hypoperfusion, leading to prevention of ischemic attacks. METHODS: A chronic cerebral hypoperfusion model induced by permanent ligation of both common carotid arteries in rats was used in this investigation. Seven days after induction of cerebral hypoperfusion, encephalomyosynangiosis (EMS) and phVEGF administration in the temporal muscle were performed. Fourteen days after treatment, the VEGF gene therapy group displayed numbers and areas of capillary vessels in temporal muscles that were 2.2 and 2.5 times greater, respectively, in comparison with the control group. In the brain, the number and area of capillary vessels in the group treated with the VEGF gene were 1.5 and 1.8 times greater, respectively, relative to the control group. CONCLUSIONS: In rat models of chronic cerebral hypoperfusion, administration of phVEGF combined with indirect vasoreconstructive surgery significantly increased capillary density in the brain. The authors' results indicate that administration of phVEGF may be an effective therapy in patients with chronic cerebral hypoperfusion, such as those with moyamoya disease.

Animals↗
PubMed2004

Quantitative analysis of radioisotope cisternography in the diagnosis of intracranial hypotension.

OBJECT: The authors attempted a quantitative analysis of conventional radioisotope cisternography for the purpose of more accurate diagnosis of intracranial hypotension. METHODS: Fifty-seven patients suspected of having intracranial hypotension underwent radioisotope cisternography. Whole-body images were obtained 2.5, 6, and 24 hours after intrathecal injection of 111In-diethylenetriamine pentaacetic acid. Radioactivity in the cerebrospinal fluid (CSF) space was counted during scanning, and radioisotope clearance was studied. Direct signs of radioisotope leakage into the spinal epidural space were found in 25 patients. Most leaks were located in the lumbosacral region. Analysis of the radioisotope clearance curve revealed two different patterns. In patients without a radiographically demonstrated radioisotope leak, absolutely exponential curves were observed (R2 > 0.99). The activity of the radioisotope decreased at a rate of e(-003) to e(-0.107) (mean +/- standard deviation, e(-0.056 +/- 0.018); 32 patients). Clearance in patients with an overt radioisotope leak was not a simple exponential curve; it could be divided into an early rapid phase and a late slow phase. The clearance rate during the first 6 hours was e(-0.219 +/- 0.127) (25 patients) and e(-0.076 +/- 0.021) thereafter. The authors speculated that the early escape of undiluted radioisotope solution through an aberrant CSF outlet, such as a traumatic spinal dural tear, was responsible for this phenomenon. CONCLUSIONS: The quantitative analysis featured in this study seems to be useful in the diagnosis of intracranial hypotension. A small CSF leak below the limit of radioisotope cisternography resolution might be detected using this technique.

Adolescent↗
PubMed2002

[Usefulness of dynamic digitized cerebral parenchymography for cerebral vascular disease].

Aortic arch injections according to Theron's method have been performed in patients with cerebral ischemia. Digital subtraction angiograms with modified windowing (low and narrow) have been used for better visualization of cerebral parenchymal condition. This "cerebral parenchymography" allows much easier understanding of cerebral parenchymal vascularization on angiographic imaging. Although further study is necessary to estimate accurate cerebral blood flow, this technique can enable an easy and quick understanding of the overall cerebral hemodynamics.

Aged↗
PubMed2002

[A review of dural arteriovenous fistulas with hemorrhagic onset].

The majority of dural arteriovenous fistulas are considered to have a benign clinical course, but some behave more aggressively, causing progressive neurological symptoms and/or intracranial hemorrhage. Several classifications of angiographic findings have been reported to predict what findings might result in catastrophic presentation. Cortical venous drainage has been described as one of the major risk factors of hemorrhage. We reviewed the records of 50 patients with dural arteriovenous fistulas admitted to our institution from 1991 to 2001 and analyzed their venous drainage patterns with reference to Cognard's classification. Six patients had hemorrhagic episodes caused by dural arteriovenous fistula and all of them had retrograde drainage through cerebral veins. The frequency of hemorrhage in Type I and IIa was 0%, in Type IIb it was 33.3%, in Type IIa + b it was 9.1%, in Type III and Type IV it was 50%, and in Type V it was 100%. These results agreed with those of Cognard reported in 1994, and we reconfirmed the usefulness of Cognard's classification. In order to adapt a firm strategy and treat them promptly and aggressively, it is important to be able to recognize what type of dural arteriovenous fistulas are perilous.

Aged↗