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Biomedical subjects

N Aoki

Publications and source records attributed to N Aoki.

At least 271 records · Page 15Linked to original sources
PubMed1993

Computed tomography features immediately after replacement of haematoma with oxygen through percutaneous subdural tapping for the treatment of chronic subdural haematoma in adults.

In an effort to achieve a simple and less invasive method for the treatment of chronic subdural haematoma, replacement of the haematoma with oxygen by percutaneous subdural tapping was employed in 36 patients. This study was conducted on 23 haematomas in 20 patients, whose computed tomography (CT) scans immediately following the treatment were available for evaluation, with particular regard to distinguishing between their findings and those seen with tension pneumocephalus. The CT features were divided into two patterns according to the location of oxygen; a convexity type (19 haematomas) and an interhemispheric type (4 haematomas). Analysis of the CT appearances revealed the oxygen was exclusively confined to the haematoma cavity, distinguishing it from the findings in tension pneumocephalus. This observation indicates the safety of replacement of the haematoma with oxygen when combined with our percutaneous subdural tapping technique which prevents lesions of the inner haematoma membrane.

Adult↗
PubMed1993

Cerebrovascular bypass surgery for the treatment of Moyamoya disease: unsatisfactory outcome in the patients presenting with intracranial hemorrhage.

While the efficacy of cerebrovascular bypass surgery for Moyamoya disease with ischemic events has been substantiated, the surgical indication for the patients presenting with intracranial hemorrhage is as yet undetermined. In an effort to prevent rebleeding from rupture of Moyamoya vessels, seven patients with intracranial hemorrhage underwent indirect bypass surgery. During the follow-up period between 2 and 11 years (mean 4.9 years), one patient suffered rebleeding 5 years after bypass surgery. Follow-up cerebral angiography failed to show revascularization and reduction of moyamoya vessels in all but one of seven patients. Thus, the author's experience suggests that bypass surgery for Moyamoya disease with hemorrhage is angiographically far less successful compared to that with ischemia. A review of the series including patients with angiographically successful revascularization and reduction of Moyamoya vessels failed to demonstrate the definitive effectiveness in eliminating the risk of further intracranial hemorrhage.

Adult↗
PubMed1993

Sensitive spectrophotometric method for the determination of ethylenediaminetetraacetic acid in foods.

A sensitive spectrophotometric method for the determination of ethylenediaminetetraacetic acid (EDTA) in foods is described. The method involves the reaction of EDTA with Fe3+ to produce the EDTA-Fe chelate, followed by the removal of excess of Fe3+ by a chelate extraction technique using chloroform and N-benzoyl-N-phenylhydroxylamine and the formation of a chromophore with 4,7-diphenyl-1,10-phenanthroline-disulfonic acid. The calibration graph was linear in the range 0.5-40.0 micrograms cm-3 of EDTA with a slope of 21.1. The relative standard deviation at 10 micrograms cm-3 of EDTA was 1.6% (n = 10). There was no interference from most of the common ingredients of commercial foods. More than 90% of EDTA added at two levels was recovered from real samples. The method was applied to the determination of EDTA in various foods, and the results obtained were compared with those given by high-performance liquid chromatography.

Edetic Acid↗
PubMed1993

Arteriovenous malformation presenting as acute subdural haematoma.

A case of acute subdural haematoma caused by ruptured arteriovenous malformation is reported. At surgery, there was no association with intracerebral haematoma or definite subarachnoid haemorrhage. The mechanism of acute subdural haematoma in the present case was considered to be rupture of an arteriolized bridging vein drained by arteriovenous malformation.

Acute Disease↗
PubMed1993

Pitfall in clipping of unruptured cerebral aneurysms: narrowing of the parent artery.

Two patients with unruptured cerebral aneurysms are presented, who were complicated by transient ischaemic neurological deficits after seemingly uneventful neck clipping. Postoperative angiography disclosed narrowing of the parent arteries. Arteriosclerotic thickening of the wall of the aneurysmal neck and the parent artery was presumed to be the cause of the narrowing. To minimize the operative morbidity in patients with unruptured aneurysms, the possibility of this phenomenon should always be borne in mind. Neck clipping procedures avoiding this pitfall are discussed.

Aged↗
PubMed1993

Urinary thrombomodulin, its isolation and characterization.

Two major molecular forms of thrombomodulin fragments present in urine were isolated from human urine by four sequential steps of column chromatography. The apparent molecular weights of these thrombomodulins estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis were 98,000 (type I) and 90,000 (type II) with dithiothreitol, and 60,000 (type I) and 55,000 (type II) without dithiothreitol. The isoelectric points of the type I and type II molecules were 2.5 and 3.8, respectively. From sequence analyses, both forms were revealed to have identical 468 amino acid sequences, Ala1-Asp468, lacking 29 amino acids of the carboxyl-terminal sequence of intact cellular thrombomodulin. Major structural differences between type I and type II were observed in the carbohydrate composition: type II had less galactosamine content than type I. Both types were active in thrombin inhibition and protein C activation, although the activities were significantly less than those of intact cellular thrombomodulin. Type I had twice as much inhibitory activity on thrombin clotting activity as type II, whereas type II was more effective as a cofactor for thrombin-catalyzed protein C activation than type I.

Amino Acid Sequence↗
PubMed1993

Functional characterization of the 5'-regulatory region of the human thrombomodulin gene.

Thrombomodulin, a glycoprotein expressed in endothelial cells, has an important role in the blood coagulation system as a modulator. Functional characterization of the 5'-regulatory region of the human thrombomodulin gene was carried out to identify elements necessary for its expression. We used a series of dissected gene constructs containing the bacterial chloramphenicol acetyltransferase gene in transient transfection assays on human umbilical vein endothelial cells. The region extending from -290 to -33 of the 5' end flanking sequence is required for the full expression of this gene. Within this region, four potential Sp1 sites were found, and the sequences of Sp1 sites were mutated to identify their role in the promoter activity of the gene, showing that the two Sp1 sites at -207 and -141 are important for the full activity of the thrombomodulin promoter. Site-directed mutation analysis identified sequence elements GCAATC at -110 as a functioning CAAT box. Another three regions, -290 to -223, -99 to -68, and -67 to -33 have unidentified positively and negatively acting elements. A silencer element was located in the region spanning from -947 to -772 bases of the 5' end flanking region. These data indicate that the expression of the thrombomodulin gene is regulated by various elements which act positively or negatively.

Base Sequence↗
PubMed1993

Establishment of a human small cell lung carcinoma cell line carrying amplification of c-myc gene and chromosomal translocation of t(3p;6p) and t(12q;17p).

A transplantable tumor and an in vitro culture cell line (GK-T3) were established from metastatic liver tissue of human small cell lung carcinoma (SCLC). Southern blot analysis revealed about 30-fold amplification of c-myc gene in the tumor cells in liver, xenografts, and in vitro cell line. The degree of c-myc amplification was essentially conserved through serial passages in nude mice and cultivation in vitro. The level of c-myc mRNA was significantly increased in these cells. Cytogenetically, numerical and complex structural abnormalities were observed in GK-T3 cells, including t(3p;6p), t(12q;17p), two homogeneously staining regions (hsrs) and several double minutes (dmins). These results suggest that activation of c-myc gene and alteration of gene(s) around these chromosomal breakpoints may play a role in tumorigenesis of GK-T3 SCLC.

Aged↗
PubMed1993

bcl-2 gene rearrangement analysis of Japanese follicular lymphomas by polymerase chain reaction in formalin-fixed, paraffin-embedded tissue specimens.

The prevalence of chromosomal translocation t(14;18) was examined in 41 cases of follicular lymphoma covering all histopathological subtypes, using the polymerase chain reaction and hybridization method with non-radioactive oligonucleotide probes. DNAs were extracted from unfixed fresh-frozen and/or formalin-fixed paraffin-embedded biopsy specimens. The t(14;18) chromosomal translocation, resulting in bcl-2-JH (immunoglobulin heavy chain gene joining segment) fusion gene, was detected in 7 (36.8%) of 19 follicular small cleaved cell lymphomas and 6 (54.5%) of 11 follicular mixed, small cleaved cell and large cell lymphomas. Meanwhile, 11 cases of follicular large cell lymphoma revealed no bcl-2-JH fusion gene. There was a statistically significant difference in the frequency of bcl-2-JH rearrangement between follicular, small cleaved cell and large cell lymphoma (two-sided Fisher exact test, P = 0.049). The difference of bcl-2 rearrangement frequency between follicular, mixed and large cell lymphoma was also statistically significant (P = 0.012).

Base Sequence↗
PubMed1993

Characterization of the promoter region of the human c-kit proto-oncogene.

The c-kit proto-oncogene encodes a tyrosine kinase receptor for stem cell factor and plays a critical role in the growth and differentiation of various types of cells including hematopoietic stem cells. To investigate the mechanisms of its transcriptional regulation, we isolated the 5' flanking region of the human c-kit gene and characterized its promoter activity in hematopoietic cells. Nucleotide sequence analysis revealed that the 1.2 kb 5' flanking region lacked a typical "TATA box," but had a relatively high G + C content and four potential Sp1-binding sites. Putative binding sites for AP-2, basic helix-loop-helix proteins, Ets-domain proteins, Myb and GATA-1 were also found. Primer extension and S1 nuclease protection analyses of hematopoietic cells indicated that the major transcription start sites are 62 bp and 58 bp upstream of the translation start site. Essentially the same start sites were detected in non-hematopoietic cells such as small cell lung carcinoma and glioblastoma: this single promoter in c-kit is different from the multiple promoter system of c-fms, a c-kit-related gene, in which at least two promoters are differently used in hematopoietic and non-hematopoietic cells. An analysis of the c-kit 5' flanking region using the bacterial chloramphenicol acetyltransferase gene (CAT assay) in human erythroleukemia HEL cells, which express the endogenous c-kit mRNA at high levels, showed that a region from -180 to -22 is important for the expression of the c-kit gene. In addition, a negative regulatory element(s) is suggested to be involved in the regulation of the c-kit gene expression in mammals.

Amino Acid Sequence↗
PubMed1993

B-raf oncogene: activation by rearrangements and assignment to human chromosome 7.

cDNA clones presumably containing a transforming gene were isolated from transformed NIH3T3 cells, which were obtained by the transfection of DNA from peripheral blood lymphocytes of a familial adenomatous polyposis patient. Sequence analysis of the cDNA clones showed that the gene contained an activated B-raf, the 5' half of which was replaced by the human small nuclear ribonucleoprotein E protein gene and an unknown gene. A partial genomic physical map of the transforming gene was made on the basis of the physical map of the cDNA clones, indicating that rearrangements had occurred during the transfection. The human B-raf gene was shown to be located on chromosome 7 by Southern blotting analysis of rodent-human somatic cell hybrid DNA using the B-raf cDNA as a probe.

3T3 Cells↗
PubMed1993

Consistent involvement of the 3' half part of the first BCR intron in adult Philadelphia-positive leukaemia without M-bcr rearrangement.

About one half of Philadelphia (Ph)-positive acute leukaemia (AL) patients and rare cases of Ph-positive chronic myelogenous leukaemia (CML) show rearrangements within the first intron of the BCR gene on chromosome 22. We studied breakpoints within the first BCR intron in 22 adult patients with Ph-positive leukaemia; 21 with AL and one with CML, which lacked rearrangements within the major bcr (M-bcr). With a series of genomic probes from this intronic region, we detected chromosomal breaks in all 22 patients within the 35 kb area, corresponding almost to the 3' half portion of the intron. The breakpoints were distributed throughout this region but we could not identify any special cluster of breakpoints in this area. Our data support consistent involvement of the 3' half part of the first BCR intron in Ph-positive leukaemias without M-bcr rearrangement, and indicate relatively wide scattering of breakpoints in this portion of the intron.

Adult↗
PubMed1993

Localization of the human alpha 2-plasmin inhibitor gene (PLI) to 17p13.

We previously assigned the human alpha 2-plasmin inhibitor gene (PLI) to 18p11.1-->q11.2 by isotopic in situ hybridization. However, results obtained subsequently via Southern blot analysis of somatic cell hybrids and fluorescence in situ hybridization studies indicate that the gene is located at 17p13. Accordingly, we reassign PLI to 17p13.

Blotting, Southern↗
PubMed1993

In vitro production of interleukin-1, interleukin-6, and tumor necrosis factor-alpha in insulin-dependent diabetes mellitus.

The in vitro production of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) by monocytes was examined in patients with insulin-dependent diabetes mellitus (IDDM), in those with noninsulin-dependent diabetes mellitus (NIDDM), and in healthy volunteers. The production of IL-1 and IL-6 by monocytes was significantly lower in IDDM patients than in NIDDM patients and normal subjects whereas the TNF-alpha production by monocytes did not differ between IDDM patients and normal subjects. On the other hand, the TNF-alpha production was significantly higher in NIDDM patients than in IDDM patients and normal subjects. There was a significant correlation between IL-1 and IL-6 concentrations in culture supernatants of monocytes for IDDM patients but not for NIDDM patients and normal subjects. Neither glucose nor insulin showed any stimulatory effect on in vitro production of these monokines. In the serial observation lasting 3-18 months, the monocyte production of IL-1 was found to be consistently reduced in IDDM patients unrelated to the control state of diabetes, suggesting that the reduction of the IL-1 and IL-6 production by monocytes in IDDM patients may be intrinsically affected by immunological defects.

Adult↗
PubMed1993

"Transinsular approach" for the treatment of a medial temporal arteriovenous malformation.

A new approach for the treatment of arteriovenous malformations in the medial temporal lobe is proposed. This approach, referred to as the "transinsular approach," comprises incising the superior part of the anterior insula and exploring the plexal point of the anterior choroidal artery through the space between the dissected insula and the frontal lobe. A representative case of a patient with a large medial temporal arteriovenous malformation that was successfully extirpated by this approach is reported. The advantages of this approach and the functional results of partial incision of the insula are discussed.

Adult↗