Kiyonobu Ikezaki

VEGF and flt Expression Time Kinetics in Rat Brain Infarct

BACKGROUND AND PURPOSE Vascular endothelial growth/vascular permeability factor (VEGF) is a candidate for an angiogenic and hyperpermeability inducing factor in an infarct because it is a secretable mitogen specific for endothelial cells and is upregulated by hypoxia. Our study attempts to clarify the chronological expression of VEGF and its receptor (flt) system in experimental cerebral infarction. METHODS With the use of a reproducible middle cerebral artery occlusion model in rats, VEGF expression was identified by Western blotting with anti-VEGF antibody. The chronological expression of the VEGF/flt system was analyzed semiquantitatively by immunohistochemical means in infarcts with different time courses from 3 hours to 3 weeks. RESULTS VEGF and flt were expressed exclusively in the ischemic brain. The bands obtained on the immunoblot at 38 and 45 kD are related to those of VEGF121 and VEGF165 isoforms. Macrophages, neurons, and glial cells chronologically expressed VEGF immunoreactivity in a different fashion. Both VEGF (bound) and flt were detected in endothelial cells along with the development of angiogenesis. CONCLUSIONS In the ischemic brain the macrophages, neurons, and glial cells appear to contain VEGF. The VEGF receptor flt was induced in endothelial cells along with the progression of angiogenesis in infarct. The VEGF/flt system is thus considered to be involved in the healing process of brain infarct.

Epidemiological features of Moyamoya disease in Japan: findings from a nationwide survey

To estimate an annual number of patients treated for Moyamoya disease in Japan and to describe the clinico-epidemiological features, a nationwide epidemiological survey was conducted in 1995. The study consisted of two questionnaires, which were distributed to departments randomly selected, of neurosurgery, neurology and pediatrics in hospitals throughout Japan. The first questionnaire inquired the number of the patients treated in 1994 and the second one detailed clinico-epidemiological information of each patient reported. Following major epidemiological findings emerged from the study: (a) The total annual number of patients treated for Moyamoya disease was estimated as 3900 (95% confidence interval (CI) 3500-4400) in Japan 1994, with the prevalence and incidence rates of 3.16 and 0.35 per 100,000 population, respectively; (b) the sex ratio (females to males) of the patients was 1.8; (c) the peak of age distribution of the patients was observed in 10-14 years old and a smaller peak in their forties; (d) the age at onset was under 10 years old in 47.8% of the patients, but some had developed the disease at the age of 25-49 years; (e) family history of Moyamoya disease was found in 10.0% of the patients; and (f) about 75% of the patients had normal activity of daily life or working ability even before treatment. The present findings were quite comparable with those obtained in the previous nationwide epidemiological survey in 1990.

Linkage of Familial Moyamoya Disease (Spontaneous Occlusion of the Circle of Willis) to Chromosome 17q25

BACKGROUND AND PURPOSE Moyamoya disease is a cerebrovascular disease of unknown cause that mainly affects Japanese children. The incidence of familial occurrence accounts for 9% of cases. The characteristic lesions of moyamoya disease are occasionally seen in neurofibromatosis type 1, of which the causative gene (NF1) has been assigned to chromosome 17q11.2. METHODS To determine whether a gene related to moyamoya disease is located on chromosome 17, we conducted microsatellite linkage analyses on 24 families containing 56 patients with moyamoya disease. Leukocyte DNA extracted from the family members was subjected to polymerase chain reaction for a total of 22 microsatellite markers on chromosome 17. The amplified polymerase chain reaction fragments were analyzed with GeneScan on an automated sequencer. RESULTS Two-point linkage analysis gave a maximum log(10) odds (LOD) score of 3.11 at the recombination fraction of 0.00 for the marker at locus D17S939. The affected pedigree member method also showed a significantly low P value (<1. 0x10(-5)) for the 5 adjacent markers at 17q25. Multipoint linkage analysis also indicated that the disease gene is contained within the 9-cM region of D17S785 to D17S836, with a maximum LOD score of 4. 58. CONCLUSIONS A gene for familial moyamoya disease is located on chromosome 17q25.

Linkage Analysis of Moyamoya Disease on Chromosome 6

Genetic factors have been suggested to contribute to the etiology of moyamoya disease. The authors have previously reported an association between moyamoya disease and several alleles for human leukocyte antigens (HLA). To further specify the genetic component of moyamoya disease, a linkage study of moyamoya disease using markers on chromosome 6, where the HLA gene is located, was performed. The 15 microsatellite markers of chromosome 6 were studied in 20 affected sibling pairs. From an identical-by-descent analysis of these markers, an allele with possible linkage to moyamoya disease was identified. Sharing of the allele among affected members in 19 families was investigated, considering the haplotype. The marker, D6S441, might be linked to moyamoya disease. Considering the haplotype, the allele was shared among the affected members in 16 (82%) of the 19 families, but not in two others. In one family, sharing of the allele could not be determined because of low heterozygosity. Further studies are necessary to clarify multiple genetic factors that are definitely linked with moyamoya disease. (J Child Neurol 2000;15:179-182).

A novel susceptibility locus for moyamoya disease on chromosome 8q23.

AbstractMoyamoya disease (MIM 252350) is characterized by stenosis or occlusion of the terminal portions of the bilateral internal carotid arteries and by abnormal vascular networks at the base of the brain. There is a high incidence of moyamoya disease in Asia, especially in Japan. Multifactorial inheritance is estimated with λs>40. Previous linkage studies have indicated that susceptibility loci for the disease are located on chromosomes 3p, 6q, and 17q. In the present study, we searched for loci linked to the disease in 12 Japanese families using 428 microsatellite markers and found significant evidence for linkage to 8q23 [maximum LOD score (MLS) of 3.6] and suggestive evidence for linkage to 12p12 (MLS=2.3). The present study revealed a novel locus for moyamoya disease.

Correlation of microanatomical localization with postoperative survival in posterior fossa ependymomas.

Twenty-two surgically treated infratentorial ependymomas were analyzed according to their anatomical origins and characteristics of extension in conjunction with the microsurgical anatomy of the fourth ventricle. The correlation between tumor origin and postoperative survival of the patients was also assessed. The tumors were classified into three types according to their origins and extensions: 1) midfloor-type: tumors originating from the caudal half of the fourth ventricular floor beneath the striae medullares. After occupying the fourth ventricular cavity, they extended downward through the foramen Magendie to the upper cervical level. 2) Lateral type: tumors arising from the vestibular area and/or the lateral recess. They grew not only inferiorly but also laterally to the cerebellomedullary cistern through the cerebellomedullary fissure and the foramen of Luschka. 3) Roof type: tumors originating from the roof of the ventricle. The overall cumulative survival rates at 2, 5, and 10 years were 84, 62, and 47%, respectively. Interestingly, the lateral-type tumors showed a significantly lower 5-year cumulative survival rate and mean survival time (21% and 40 months) when compared with midfloor-type tumors (73% and 170 months). Because the tumor originates near the vital neural structures and because each type has characteristics of extension, a clear knowledge of the microanatomical relationship between the tumor and the surrounding structures would be of great benefit for improving the operative outcome of posterior fossa ependymomas.

Rational Approach to Treatment of Moyamoya Disease in Childhood

Early diagnosis and treatment of moyamoya disease in children is essential to minimize residual mental and physiologic deficits. Current treatment of childhood moyamoya disease in Japan, preoperative evaluation of perfusion reserve as a surgical indication, and the role of noninvasive follow-up by magnetic resonance angiography are reported. Approximately 20% of children with definite moyamoya disease were observed or treated medically. Among surgical procedures, single indirect bypass surgery was used in approximately 30% of all patients; combinations of direct and indirect bypass surgery, 20%; and multiple-indirect bypass surgery, 18%. Both adequate understanding of the primary condition and determination of optimal treatment, including specific operative procedures, required evaluation of cerebral circulation and metabolism. Surgical indications included reduced perfusion reserve in affected brain by positron emission tomography or single photon emission tomography with administration of acetazolamide or a CO 2 load. Postoperative improvements of cerebral perfusion reserve show better correlation with disappearance of ischemic attacks than does angiographically demonstrated collateral formation. Follow-up evaluation with magnetic resonance angiography has advantages over conventional angiography because it is noninvasive and avoids general anesthesia. (J Child Neurol 2000;15:350-356).

Trigeminal neuralgia: Differentiation between intracranial mass lesions and ordinary vascular compression as causative lesions

We investigated 164 patients who presented with trigeminal neuralgia as their initial symptom at our institute. Twenty-two patients (13.4%) had intracranial causative lesions other than vascular compression. There were 19 tumors (10 epidermoids, 5 meningiomas, and 4 neurinomas) and 3 vascular lesions (2 arteriovenous malformations and 1 aneurysm). Eleven patients (50%) demonstrated only trigeminal neuralgia without any other neurological deficits. Preoperative computed tomography could not identify any causative lesions in 6 of these 22 patients. In 3 of the 6 patients, a causative lesion was clearly detected only by magnetic resonance imaging, while in 1 of the 6 patients an arteriovenous malformation was detected by angiography alone. Intraoperatively tumor was encountered in 3 cases even though preoperative computed tomography could not detect any apparent causative lesions. A higher incidence of hypesthesia in the trigeminal nerve regions as well as a reduced corneal reflex was noted in patients with a mass lesion compared to those with vascular compression. We thus conclude that magnetic resonance imaging should be performed on all patients who complain of trigeminal neuralgia in order to rule out mass lesions, however, angiography is still considered useful for the diagnosis of some vascular lesions.

The current status of the treatment for hemorrhagic type Moyamoya disease based on a 1995 nationwide survey in Japan

The optimal treatment regimen for hemorrhagic type Moyamoya disease has yet to be clearly established. Furthermore, it remains unclear as to whether or not bypass surgery can help prevent future intracranial hemorrhaging in Moyamoya patients. In Japan, several treatment options, such as conservative, medical, and surgical intervention, have been employed for the treatment of hemorrhagic type of Moyamoya disease. In this study, 282 hemispheres with hemorrhagic onset were analyzed based on a 1995 nationwide survey by the Research Committee on Spontaneous Occlusion of the Circle of Willis (Moyamoya Disease) of the Ministry of Health and Welfare Japan to clarify the current status of treatment for hemorrhagic type Moyamoya disease. Questionnaires were distributed to the departments of neurology, neurosurgery, and pediatrics all over Japan asking about both treatment and rebleeding. As a result, 12.5% of the affected hemispheres were treated conservatively while 32.3% were medically treated. Ventricular drainage and/or hematoma removal was performed in 15.8%, and revascularization surgery in 38.3% of all hemorrhagic sides. Among the revascularization procedures used, 45.7% of the hemispheres underwent single indirect bypass surgery, such as EDAS while 22.2% of them received a direct (superficial temporal artery--middle cerebral artery: STA-MCA) bypass surgery. A combination of direct and indirect bypass surgery or a combination of different kinds of indirect procedures comprised 32.1%. Forty-nine out of 282 hemorrhagic hemispheres demonstrated rebleeding. An intracranial hemorrhage occurred in 15 hemispheres with ischemic onset even though nine of them had undergone bypass surgery prior to hemorrhaging. Nearly 18% of the patients with hemorrhagic type disease experienced rebleeding regardless of the treatment modalities. Based on these findings, there remains no clearly superior treatment plan for hemorrhagic Moyamoya disease to prevent rebleeding at this time. However, the selection of patients, treatment modalities, and the timing of the surgery might all play an important role in controlling rebleeding. The final outcome of the patients are therefore mainly considered to correlate with the initial severity of the clinical features.

Bleomycin-resistant cells contain increased bleomycin-hydrolase activities

Summary We have previously isolated mutants relatively resistant to bleomycin, a potent anticancer agent, from mutagenized Chinese hamster ovary (CHO) cells that are more sensitive to the antibiotic (BLMS). Three bleomycin-resistant mutants (BLMR-1, -3, -4) showed higher bleomycin-inactivating activity than the parental CHO cell (BLMS), using an assay for DNA degradation to measure active drug. A hybrid clone, CBH-1, derived from a BLMR × BLMS cell fusion, was as resistant to bleomycin-A2 as was BLMR-1; it also contained increased bleomycin-inactivating activity comparable to that in BLMR-1 cells. Bleomycin-hydrolase activity of these cell lines was compared in cell-free extracts by assaying the conversion of bleomycin into its deamidated form. The specific activities of bleomycin hydrolase in the BLMR clones were shown to be 2–3 fold higher than that in CHO cells.