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Kiyoshi Ito

Publications and source records attributed to Kiyoshi Ito.

At least 55 records · Page 3Linked to original sources
PubMed2004

Clinical experience with combination paclitaxel and carboplatin therapy for advanced or recurrent carcinosarcoma of the uterus.

OBJECTIVE: The purpose of the study was to evaluate the efficacy of combination chemotherapy with paclitaxel and carboplatin in patients with advanced or recurrent carcinosarcoma of the uterus. METHODS: A retrospective review was carried out at Miyagi Prefecture Cancer Research Center Hospital. Six patients pathologically diagnosed with uterine carcinosarcoma were treated with paclitaxel (175 mg/m(2) given intravenously over 3 h) and carboplatin (dosed at AUC 6) every 3 weeks at our center between 1997 and 2003. Responses and adverse effects were assessed according to Response Evaluation Criteria in Solid Tumors and National Cancer Institute-Common Toxic Criteria, respectively. RESULTS: All six patients were evaluable for toxicity, and no unacceptably severe toxicities were reported. Grades 3 and 4 hematologic toxicities occurred, but all of them were overcome by adequate treatment with granulocyte colony-stimulating factor and blood transfusions. Five of six patients had measurable disease and thus were evaluable for response: Four patients had a complete response (CR) and the remaining patient had progressive disease (PD). The median progression-free interval (PFI) for all six cases was 18 months, with a median overall survival of 25 months. CONCLUSIONS: Although the number of cases was small, the regimen evaluated in the current study demonstrated higher activity and lesser toxicity than those found in previous studies in patients with advanced or recurrent uterine carcinosarcoma. Additional phase II clinical studies are necessary to evaluate fully the benefits of this regimen.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

E4F1, a novel estrogen-responsive gene in possible atheroprotection, revealed by microarray analysis.

Estrogen has been postulated to be involved in inhibition of vascular smooth muscle cell (VSMC) proliferation mainly via estrogen receptor (ER), but the detailed mechanism has remained primarily unknown. Therefore, in this study, microarray analysis was used in two types of cultured human VSMCs: one positive for ER alpha, and the other for ER beta, which were treated by estrogens to detect the estrogen-responsive genes. We also used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate mRNA levels of selective target gene (TG) in these cells. We further studied whether the TG product was involved in inhibition of proliferation using small interfering RNA (siRNA) of the TG transfection. We subsequently used quantitative RT-PCR and in situ hybridization analysis to evaluate the expression of these gene products in human aorta. E4F1, a possible inducer of cell growth arrest, was markedly increased only in ER alpha-positive VSMCs by estrogens in both microarray and RT-PCR analyses. Blocking of E4F1 using siRNA suppressed estrogenic inhibition of ER alpha-positive VSMC proliferation. E4F1 mRNA was abundant in premenopausal female aorta with mild atherosclerotic changes. E4F1 is therefore considered one of the estrogen-responsive genes involving ER alpha-mediated inhibition of VSMC proliferation and may play an important role in estrogen-related atheroprotection of human aorta.

Adenovirus E4 Proteins↗
PubMed2004

A hap1 mutation in a laboratory strain of Saccharomyces cerevisiae results in decreased expression of ergosterol-related genes and cellular ergosterol content compared to sake yeast.

DNA microarray and Northern blot analysis revealed that a sake yeast strain Kyokai no. 7 (K7) showed higher expression of genes encoding proteins involved in ergosterol biosynthesis than a laboratory yeast strain X2180. We hypothesized that these differences in expression levels were caused by a defect of a transcriptional factor Hap1, because strain X2180 contained a Ty1 insertion mutation in the HAP1 gene. To confirm this, we constructed a strain X2180 derivative (strain HX) that contained the wild-type HAP1 genes originating from strain K7. The expression levels of ergosterol-related genes and cellular ergosterol content in strain HX were higher than those in strain X2180 and were almost comparable to those in strain K7. These results suggest that the differences in the expression levels of ergosterol-related genes and ergosterol content between strains K7 and X2180 were largely caused by the hap1 mutation in strain X2180. Involvement of the mutated Hap1 in the differential gene expression between strain K7 and strain X2180 was further confirmed by a lacZ reporter assay of HMG1, one of the Hap1-regulated genes. We also revealed that the HMG1 promoter region between -500 and -376 was important in the transcriptional activation by Hap1.

Journal Article↗
PubMed2004

Cloning and analysis of the AWA1 gene of a nonfoaming mutant of a sake yeast.

Almost all sake yeasts form a thick foam layer on sake mash during fermentation. To reduce the amount of foam, nonfoaming mutants were bred from foam-forming sake yeasts. To elucidate the mechanism of this foam formation, we have cloned a gene from a foam-forming sake yeast that confers foam-forming ability to a nonfoaming mutant. This gene, named AWA1, encodes a glycosylphosphatidylinositol (GPI) anchor protein that is localized to the cell wall and is required for cell surface hydrophobicity. In this paper, we describe the genomic analysis of the AWA1 gene in a nonfoaming mutant strain K701 derived from a foam-forming sake yeast strain K7. K701-AWA1 was cloned in a cosmid and its sequence was compared with that of K7-AWA1. Although the 5' half of K701-AWA1 was identical to that of K7-AWA1, the 3' half of K701-AWA1 was different from that of K7-AWA1, resulting in a loss of the C-terminal hydrophobic sequence of Awa1p. Since this sequence is considered to be required for the anchoring of Awa1p to the cell wall, K7-Awa1p could not confer both cell surface hydrophobicity and foam-forming ability to strain K701 cells. Since the change found in K701-AWA1 was not a point mutation but a larger scale event, we analyzed chromosome rearrangement by pulsed-field gel electrophoresis Southern blot analyses. The results suggest that the left subtelomeric region of chromosome IX in strain K7 was translocated to the AWA1 gene in chromosome XV by a nonreciprocal recombination.

Journal Article↗
PubMed2004

Gastrointestinal immunophenotype in adenocarcinomas of the uterine cervix and related glandular lesions: a possible link between lobular endocervical glandular hyperplasia/pyloric gland metaplasia and 'adenoma malignum'.

Gastrointestinal phenotype in cervical adenocarcinomas was examined by immunohistochemistry and correlated with morphologic features. Antibody panels included anti-MUC2, MUC6, CD10, chromogranin A (CGA) and HIK1083. In addition, expression of p16INK4, a cyclin-dependent kinase inhibitor which is expressed in a variety of high-risk HPV-related conditions, was studied. A total of 94 invasive adenocarcinomas including 20 minimal deviation adenocarcinomas (MDAs) and 72 adenocarcinomas in situ (AIS) were examined. MDAs were most frequently positive for HIK1083 and/or MUC6, two representative gastric markers, with a rate of 95%, followed by intestinal-type adenocarcinomas (IAs) with a rate of 85% whereas only 27% of 56 usual endocervical-type adenocarcinomas (UEAs) were positive. MUC2, a goblet cell marker, was positive in 85% and 25% of IAs and MDAs, respectively, while in only 14% of UEAs. CD10 was positive in 15% of IAs, indicating incomplete intestinal differentiation without a brush border in most of the cases. CGA-positive cells were frequently seen in MDAs and IAs with rates of 60% and 62%, respectively. Nuclear and cytoplasmic p16INK4 positivity was identified in 93% of UEAs, whereas 30% of MDAs were positive for p16INK4. Results in AISs were comparable to their invasive counterparts, but morphologically usual-type AISs identified in eight cases of MDA were frequently positive for HIK1083 (75%) and MUC6 (63%), and p16INK4. Of note was the existence of lobular endocervical glandular hyperplasia (LEGH) with atypical features including cytologic abnormalities, and/or papillary projection, which were identified in this study in pure form (n=3) or in association with MDAs (n=6), but not in cases of other types of adenocarcinomas. These observations indicate that gastrointestinal phenotype is frequently expressed in MDAs and IAs, and there seems to be a possible link between MDA, and LEGH and morphologically usual-type AIS with gastric immunophenotype in histogenesis. Frequent absence of p16INK4 expression in MDAs suggests a possibility that high-risk HPV does not play a crucial role in development of MDAs, in contrast to the majority of endocervical adenocarcinomas. p16INK4 immunohistochemistry appears to be a promising diagnostic tool, but pathologists should be aware of frequent negative staining in MDAs, which can be a source of erroneous diagnosis.

Adenocarcinoma↗
PubMed2004

Mutational and structural analysis of cobalt-containing nitrile hydratase on substrate and metal binding.

Mutants of a cobalt-containing nitrile hydratase (NHase, EC 4.2.1.84) from Pseudonocardia thermophila JCM 3095 involved in substrate binding, catalysis and formation of the active center were constructed, and their characteristics and crystal structures were investigated. As expected from the structure of the substrate binding pocket, the wild-type enzyme showed significantly lower K(m) and K(i) values for aromatic substrates and inhibitors, respectively, than aliphatic ones. In the crystal structure of a complex with an inhibitor (n-butyric acid) the hydroxyl group of betaTyr68 formed hydrogen bonds with both n-butyric acid and alphaSer112, which is located in the active center. The betaY68F mutant showed an elevated K(m) value and a significantly decreased k(cat) value. The apoenzyme, which contains no detectable cobalt atom, was prepared from Escherichia coli cells grown in medium without cobalt ions. It showed no detectable activity. A disulfide bond between alphaCys108 and alphaCys113 was formed in the apoenzyme structure. In the highly conserved sequence motif in the cysteine cluster region, two positions are exclusively conserved in cobalt-containing or iron-containing nitrile hydratases. Two mutants (alphaT109S and alphaY114T) were constructed, each residue being replaced with an iron-containing one. The alphaT109S mutant showed similar characteristics to the wild-type enzyme. However, the alphaY114T mutant showed a very low cobalt content and catalytic activity compared with the wild-type enzyme, and oxidative modifications of alphaCys111 and alphaCys113 residues were not observed. The alphaTyr114 residue may be involved in the interaction with the nitrile hydratase activator protein of P. thermophila.

Actinomycetales↗
PubMed2004

Novel prolyl tri/tetra-peptidyl aminopeptidase from Streptomyces mobaraensis: substrate specificity and enzyme gene cloning.

The prolyl peptidase that removes the tetra-peptide of pro-transglutaminase was purified from Streptomyces mobaraensis mycelia. The substrate specificity of the enzyme using synthetic peptide substrates showed proline-specific activity with not only tripeptidyl peptidase activity, but also tetrapeptidyl peptidase activity. However, the enzyme had no other exo- and endo-activities. This substrate specificity is different from proline specific peptidases so far reported. The enzyme gene was cloned, based on the direct N-terminal amino acid sequence of the purified enzyme, and the entire nucleotide sequence of the coding region was determined. The deduced amino acid sequence revealed an N-terminal signal peptide sequence (33 amino acids) followed by the mature protein comprising 444 amino acid residues. This enzyme shows no remarkable homology with enzymes belonging to the prolyl oligopeptidase family, but has about 65% identity with three tripeptidyl peptidases from Streptomyces lividans, Streptomyces coelicolor, and Streptomyces avermitilis. Based on its substrate specificity, a new name, "prolyl tri/tetra-peptidyl aminopeptidase," is proposed for the enzyme.

Amino Acid Sequence↗
PubMed2004

Promoter methylation status and expression of TMS1 gene in human epithelial ovarian cancer.

Gene silencing associated with aberrant DNA methylation of promoter CpG islands is one mechanism through which tumor suppressor genes are inactivated in human cancers. TMS1 (target of methylation-induced silencing) is a CpG island-associated gene that functions in the regulation of apoptosis. In this study, we examined the DNA methylation status of the TMS1 promoter in ovarian cancer cell lines and tissues by methylation-specific PCR (MSP) and its mRNA expression by reverse transcription and quantitative PCR. Aberrant methylation of TMS1 was present in 7/12 ovarian cancer cell lines and 8/20 primary ovarian cancer tissues. The median value of relative TMS1 gene expression in cancers with methylation (0.15) was significantly lower than that in cancers without methylation (13.9) (P < 0.001). The expression of the TMS1 gene was relatively high (48.5) in the normal ovarian cDNA library. TMS1 gene expression was restored by treatment with the demethylating agent 5-aza-2'-deoxycitidine in the OV90 cell line, which lacks the TMS1 transcript. Our results suggest that aberrant methylation of TMS1 may play a role in the pathogenesis of ovarian cancer.

CARD Signaling Adaptor Proteins↗
PubMed2004

Use of Mammalian eggs for assessment of human sperm function: molecular and cellular analyses of fertilization by intracytoplasmic sperm injection.

PROBLEMS: Intracytoplasmic sperm injection (ICSI ) has been described as the 'cure' for male sterility because a single sperm can now be directly introduced into an egg with some chance of pregnancy. While ICSI has revolutionized the practice of assisted reproductive techniques (ART), there are few molecular and cellular studies about its safety and efficacy. Even by using ICSI, fertilization in humans succeeds only if the sperm effectively accomplishes a number of tasks including 'post-ICSI events' in fertilization. To assess the function of human sperm after ICSI, we used heterologous ICSI with human sperm into animal eggs. Egg activation, sperm decondensation and sperm centorosomal function were examined in sperm from fertile men and infertile patients. METHODS: Sperm from fertile men and infertile patients were injected into hamster, rabbit and bovine eggs by Piezo micromanipulator, and studied in decondensation of sperm nuclei, egg activation and microtubule organization. RESULTS: Decondensation human sperm head following ICSI into hamster eggs occurred initially form basal lesion, and apical portion of sperm nuclei which is surrounded by acrosome and perinuclear theca, still condensed in early pronuclear stage. Radial array of microtubules from sperm centrosome 'sperm aster' which is essential for pronuclear movement was observed in 30% rabbit eggs following ICSI with human sperm. By heterologous ICSI system with fertile human sperm and bovine eggs, 83.3% of eggs was activated and 60% eggs had sperm aster, indicating that bovine Piezo ICSI system is appropriate for assessing human sperm oocyte activation ability and human sperm centrosomal function. Oocyte activation and sperm centrosomal function were significantly low in sperm from men with globozoospermia and men with dysplasia of fibrous sheath. CONCLUSION: These assays indicate differences of the process of fertilization between in vitro fertilization and ICSI, and reflect the human sperm function especially for the 'post-ICSI events' in fertilization. More molecular and cellular analyses in fertilization by ICSI are needed for improvement of ART.

Acrosome↗
PubMed2004

A temperature-sensitive dcw1 mutant of Saccharomyces cerevisiae is cell cycle arrested with small buds which have aberrant cell walls.

Dcw1p and Dfg5p in Saccharomyces cerevisiae are homologous proteins that were previously shown to be involved in cell wall biogenesis and to be essential for growth. Dcw1p was found to be a glycosylphosphatidylinositol-anchored membrane protein. To investigate the roles of these proteins in cell wall biogenesis and cell growth, we constructed mutant alleles of DCW1 by random mutagenesis, introduced them into a Deltadcw1 Deltadfg5 background, and isolated a temperature-sensitive mutant, DC61 (dcw1-3 Deltadfg5). When DC61 cells were incubated at 37 degrees C, most cells had small buds, with areas less than 20% of those of the mother cells. This result indicates that DC61 cells arrest growth with small buds at 37 degrees C. At 37 degrees C, fewer DC61 cells had 1N DNA content and most of them still had a single nucleus located apart from the bud neck. In addition, in DC61 cells incubated at 37 degrees C, bipolar spindles were not formed. These results indicate that DC61 cells, when incubated at 37 degrees C, are cell cycle arrested after DNA replication and prior to the separation of spindle pole bodies. The small buds of DC61 accumulated chitin in the bud cortex, and some of them were lysed, which indicates that they had aberrant cell walls. A temperature-sensitive dfg5 mutant, DF66 (Deltadcw1 dfg5-29), showed similar phenotypes. DCW1 and DFG5 mRNA levels peaked in the G1 and S phases, respectively. These results indicate that Dcw1p and Dfg5p are involved in bud formation through their involvement in biogenesis of the bud cell wall.

Actins↗
PubMed2004

Isolated torsion of the distal part of the fallopian tube in a premenarcheal 12 year old girl: a case report.

Isolated torsion of the fallopian tube in premenarcheal girls is very rare. However, correct diagnosis and treatment are needed in order to optimize salvage of fallopian tube. Here, we report a case of fallopian tube torsion in a premenarcheal girl. A 12-year-old premenarcheal girl was admitted with a rapid history of colicky lower abdominal pain. MR image demonstrated normal ovaries and a large spherical cystic tumor with hemorrhage-like contents. The differential diagnosis included torsion of a para-ovarian cyst or hydrosalpinx, hemorrhage within a non-communicating uterine horn or a pelvic hemorrhage of unknown origin. Laparoscopic inspection/operation was performed. The distal portion of the left fallopian tube was swollen with two twists evident in the middle portion. The distal portion of the left fallopian tube was laparoscopically removed with the aid of a YAG laser. The mechanisms underlying disorders of the left fallopian tube are not well understood. However, some intrinsic/extrinsic causative factors are discussed. Although torsion of the fallopian tube occurs rarely and exhibits variable clinical features, the diagnosis should be considered in all young girls presenting with sudden colicky abdominal pain. Laparoscopic inspection/surgery appears to be the most suitable management.

Abdominal Pain↗
PubMed2004

Cervical cytologic examination during physical checkup of pregnant women: cervical cancer screening in women under the age of thirty.

Recently, the Ministry of Health, Labor and Welfare proposed that cervical cancer screening should be conducted for women aged 20 to 29 years old in Japan. However, there are insufficient data available in Japan concerning the screening conducted for women under the age of 30. Therefore, we made a survey of the results of cervical cytologic examination for pregnant women. 28,616 pregnant women were examined as subjects of a study group. A group of 108,289 women, subjected to group screening for cervical cancer in Miyagi Prefecture, were studied as a control group. The rate of subjects who required close examination in the pregnant women's group was significantly higher than that in the mass screening group (1.12% vs. 0.84%). The rate of close examination was significantly higher in the women 19 years old or younger compared to those in the age group of 25 to 39 years old. The rate was also significantly higher in women aged 20 to 24 years old than those who are 25 to 34 years old. Of the 321 subjects who required close examination, 34 cases underwent treatment, and 17 cases were under age 30. Moreover, all three cases of microinvasive and/or invasive carcinoma were under the age of 30 years (23, 23, 27 years old, respectively). Our results suggest that screening for cervical cancer in pregnancy is a useful means to find cervical neoplasia in young women and is effective in reducing the cervical cancer morbidity rate.

Adult↗
PubMed2004

Retrospective analysis of concurrent chemoradiation with the combination of bleomycin, ifosfamide and cisplatin (BIP) for uterine cervical cancer.

Combination chemotherapy consisting of bleomycin, ifosfamide, and ciplatin (BIP) is recognized as one of the most effective chemotherapies for uterine cervical cancer. However, there have been no reports that evaluate concurrent use of radiation with BIP. The objective of this study was to evaluate the toxicity and response of the combination of BIP concurrent with radiation in patients with squamous cell carcinoma of the uterine cervix. Eligibility criteria included patients who underwent radical hysterectomy (Type III hysterectomy) as a primary treatment and revealed lymph node metastases or deep myometrial invasion (stage IB and IIA) and patients who were previously untreated (stage IIB-IV). All of the patients had biopsy-proven squamous cell carcinoma of the uterine cervix. The patients received three courses of BIP chemoradiation, and the response and toxicity were evaluated. From January 2000 to December 2003, 30 patients met study eligibility criteria. All but three patients completed 3 courses of planned chemotherapy. The frequency of severe (grade 3 and 4) toxicity was as follows: anemia, 46.7%; neutrocytopenia, 73.3%; thrombocytopenia, 16.7%; and nausea and vomiting, 23.3%. Among 30 patients, 22 cases were evaluated for response. Complete response was achieved in 16 (72.7%) of patients, with a response rate of 90.9%. In conclusion, BIP chemoradiation seems to be superior to previously reported chemoradiation regimens, and has a potential as an optimal combination chemotherapy concurrent with radiation.

Adult↗
PubMed2003

Novel inhibitor for prolyl aminopeptidase from Serratia marcescens and studies on the mechanism of substrate recognition of the enzyme using the inhibitor.

Prolyl aminopeptidase from Serratia marcescens hydrolyzed x-beta-naphthylamides (x=prolyl, alanyl, sarcosinyl, L-alpha-aminobutylyl, and norvalyl), which suggested that the enzyme has a pocket for a five-member ring. Based on the substrate specificity, novel inhibitors of Pro, Ala, and Sar having 2-tert-butyl-[1,3,4]oxadiazole (TBODA) were synthesized. The K(i) value of Pro-TBODA, Ala-TBODA, and Sar-TBODA was 0.5 microM, 1.6 microM, and 12mM, respectively. The crystal structure of enzyme-Pro-TBODA complex was determined. Pro-TBODA was located at the active site. Four electrostatic interactions were located between the enzyme and the amino group of Pro inhibitors (Glu204:0E1-N:Inh, Glu204:0E2-N:Inh, Glu232:0E1-N:Inh, and Gly46:O-N:Inh), and the residue of the inhibitors was inserted into the hydrophobic pocket composed of Phe139, Leu141, Leu146, Tyr149, Tyr150, and Phe236. The roles of Phe139, Tyr149, and Phe236 in the hydrophobic pocket and Glu204 and Glu232 in the electrostatic interactions were confirmed by site-directed mutagenesis, which indicated that the molecular recognition of proline is achieved through four electrostatic interactions and an insertion in the hydrophobic pocket of the enzyme.

Alanine↗
PubMed2003

Crystal structure of glutathione-independent formaldehyde dehydrogenase.

Formaldehyde dehydrogenase from Pseudomonas putida (PFDH) is a member of the zinc-containing medium-chain alcohol dehydrogenase (ADH) family. The pyridine nucleotide NAD(H) in PFDH, which is distinct from the coenzyme (as co-substrate) in typical ADHs, is tightly but not covalently bound to the protein and acts as a cofactor. Such enzymes with tightly bound NAD(P)(H) acting as a cofactor are called nicotinoproteins. The structural basis of the tightly bound cofactor of PFDH is unknown. The crystal structure of PFDH has been solved by the multiwavelength anomalous diffraction method using intrinsic zinc ions and has been refined at a 1.65 A resolution. The 170-kDa-homotetrameric PFDH molecule shows 222-point group symmetry. Although the secondary structure arrangement and the binding mode of catalytic and structural zinc ions in PFDH are similar to those of typical ADHs, a number of loop structures that differ between PFDH and ADHs in their lengths and conformations are observed.

Aldehyde Oxidoreductases↗
PubMed2003

Prognostic significance of second-look laparotomy for surgically confirmed early-stage epithelial ovarian cancer: a multicenter retrospective study.

BACKGROUND: In the present study, we conducted a multicenter retrospective analysis to elucidate the prognostic significance of second-look laparotomy (SLL) in early-stage epithelial ovarian cancer that was confirmed by complete surgical exploration. METHODS: In July 2001, 12 Japanese institutions received questionnaires regarding patients with early-stage epithelial ovarian cancer and SLL. Eligibility criteria included patients with stage I or II epithelial ovarian cancer who were surgically diagnosed between January 1988 and December 1997. Data were collected regarding age, performance status, tumor histologic subtype, stage, preoperative carbohydrate antigen (CA) 125 level, results of SLL if performed, recurrence, disease-free survival, and overall survival. Survival analyses and comparisons were performed by univariate methods. RESULTS: There were 87 patients who met the eligibility criteria. There were no significant differences in the backgrounds of patients who had had SLL ( n = 30) and the non-SLL group ( n = 57). Of the 30 SLL-group patients, 28 had negative SLL findings and 2 had positive findings. Six and 5 patients in the SLL group and the non-SLL group, respectively, had recurrence ( P = 0.177), and 4 patients in the SLL group had a recurrence after "negative" SLL findings. There was no significant difference between the two groups for either overall ( P = 0.73) or disease-free survival ( P = 0.273). On univariate analysis, only clear-cell histology was associated with a poor prognosis in early-stage epithelial ovarian cancer ( P = 0.031). CONCLUSION: SLL is not beneficial for early-stage epithelial ovarian cancer. More favorable outcomes will be achieved for early-stage patients with the improvement of treatment for clear-cell adenocarcinoma.

Adult↗
PubMed2003

Aneurysm at the posterior inferior cerebellar artery of extradural origin for preoperative evaluation of safe clipping: case report and review of the literature.

BACKGROUND: As far as we know, 6 cases of extracranial (including craniocervical junction) intradural aneurysms of the posterior inferior cerebellar artery have been previously reported. However, preoperative detailed evaluation of the origin site and a course of the posterior inferior cerebellar artery by means of angiography were not reported in previous papers. CASE DESCRIPTION: We report a rare case of aneurysm of the posterior inferior cerebellar artery, which originated extradurally from the right vertebral artery. A 69-year-old woman experienced a sudden headache 16 years ago and a computed tomography scan showed a subarachnoid hemorrhage around the midbrain. Four-vessel cerebral angiography, however, failed to disclose a source of the hemorrhage. Magnetic resonance angiography incidentally revealed an aneurysm at the craniocervical junction 16 years after the subarachnoid hemorrhage. The aneurysm was exposed and clipped via a suboccipital route. At surgery, it was of no use to apply a temporary clip on the intradural segment of the vertebral artery, because the posterior inferior cerebellar artery was found to enter the intradural space separately from the vertebral artery. The blood flow to such an aneurysm cannot be stopped with this procedure. CONCLUSIONS: Careful neuroimaging study is essential for the accurate diagnosis and successful treatment of such a rare aneurysm.

Aged↗