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Biomedical subjects

T Sekiya

Publications and source records attributed to T Sekiya.

At least 19 recordsLinked to original sources
PubMed1992

Aberrations of the p53 tumor suppressor gene in human non-small cell carcinomas of the lung.

Aberrations of the p53 gene in 115 surgical specimens of non-small cell carcinomas of the lung were examined by single-strand conformation polymorphism analysis of polymerase chain reaction products. Structural abnormalities of the p53 gene were observed in 60 tumors (52%), i.e., 8 of 14 large cell carcinomas, 24 of 58 adenocarcinomas, 25 of 37 squamous cell carcinomas, and 3 of 6 adenosquamous carcinomas. Direct sequencing of abnormal DNA fragments revealed 45 single-base substitutions, 9 deletions or insertion of a short nucleotide sequence, and 3 two-base substitutions in 57 tumors. In the other 3 tumors, loss of one of the p53 alleles was observed, with no mutation in the other allele. Allelic loss of the p53 gene was observed in 14 of 43 informative cases (33%), and in 11 of the 14 cases the remaining allele was mutated. The aberrations of the p53 gene were not limited to a particular histological type or clinical stage. Their high frequency suggests that they were involved in the genesis of non-small cell carcinomas of the lung. The mutation frequency (46%) of the p53 gene in tumors carrying mutated ras genes was essentially the same as the overall frequency in lung cancers, suggesting that accumulation of mutations in these two genes in a tumor is a random phenomenon.

Base Sequence↗
PubMed1992

Two nucleotides next to the anticodon of cytoplasmic rat tRNA(Asp) are likely generated by RNA editing.

The nucleotide sequences of major cytoplasmic tRNA(Asp) from rat liver and rat ascites hepatoma comprise a U32 and C33 next to the anticodon as was confirmed by different procedures. Additionally we identified a tRNA(Asp) with C32 and U33 in a minor proportion. We have shown earlier that the tRNA(Asp) gene is part of a cluster of tRNA genes which is amplified at least ten times in the rat nuclear genome. Six independent isolated clones display identical sequences in the coding region of the tRNA(Asp) gene which differ from tRNA(Asp) in having C32 and T33. Using a combination of single-strand conformation polymorphism (SSCP) analyses and direct sequencing of polymerase chain reaction (PCR) products we have now demonstrated that no variant allele of the tRNA(Asp) gene with T32 and C33 exists in the rat genome. Together with the RNA sequencing data these findings strongly indicate that major rat tRNA(Asp) is generated by post-transcriptional pyrimidine transitions at positions 32 and 33 and that the minor tRNA(Asp) is its unedited precursor.

Animals↗
PubMed1992

Detection of a common mutation of the catalase gene in Japanese acatalasemic patients.

Acatalasemia was one of the earliest described genetic enzyme defects. In 1990, a causal point mutation (a splicing mutation) was first reported in a Japanese patient with acatalasemia. In the present study, the polymerase chain reaction and single-strand conformation polymorphism analysis were used to determine whether the same point mutation was present in unrelated Japanese patients. The subjects studied were the previously examined acatalasemic female, her brother, who is hypocatalasemic, and two other unrelated acatalasemic patients. A single G to A point mutation at the fifth position of intron 4, identical to that previously found, was present in all the studied patients. This finding strongly suggests that only a single mutated allele has spread in the Japanese population.

Acatalasia↗
PubMed1992

A ring electrode to record extraocular muscle activities during skull base surgery.

A ring-shaped electrode was developed and used in 20 patients to record evoked electromyographic responses directly from the extraocular muscles during skull base surgery. Intra-operative monitoring with this electrode helps the surgeon to localize the nerves that innervate the extraocular muscles precisely and to refrain from disturbing important neural structures during operations. Such monitoring also provides some insight into the pathophysiology of the dysfunction of these nerves resulting from skull base lesions.

Abducens Nerve↗
PubMed1992

Cloning and polymerase chain reaction-single-strand conformation polymorphism analysis of anonymous Alu repeats on chromosome 11.

We have shown that many of the Alu repeats found in the GenBank database are polymorphic and that this polymorphism can be detected by a simple technique, single-strand conformation polymorphism (SSCP) analysis, after polymerase chain reaction (PCR) amplification of each repeat from DNA of individuals. Here, we describe a method for collecting many anonymous Alu repeats and their flanks in a chromosome-specific phage library and cloning them into plasmids. The flanking single-copy sequences of each repeat in the plasmid were then determined, and 20mer to 30mer segments of these sequences were used as primers for the PCR-SSCP analysis. Many new polymorphic DNA markers on chromosome 11 were obtained with this method. These markers can also serve as sequence-tagged sites for physical mapping of the genome.

Bacteriophages↗
PubMed1992

F-SSCP: fluorescence-based polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis.

A fluorescence-based method for polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis, F-SSCP, was developed in which the target sequence is amplified by the PCR using fluorescent primers. The amplified products are then heat-denatured and applied to a water-jacket controlled gel in an automated DNA sequencer. The separated strands are detected as laser-excited fluorescence at the bottom of the gel, and mutations are detected as shifts in the position of the peaks in the fluorogram. The system does not involve radioactivity, and the conditions of electrophoresis are more strictly controlled than in the previous system, which relied on ambient air-cooling to maintain the gel at a constant temperature. The nature of the output data allows direct quantitative interpretation, and so the relative abundance of each allele in a mixture of two or more alleles can easily be estimated. The application of F-SSCP for detection of mutations and loss of heterozygosities of p53 in tumor tissues is reported.

Base Sequence↗
PubMed1992

Absence of activating mutations in the transmembrane domain of the c-erbB-2 protooncogene in human lung cancer.

The rat neu gene is known to be activated by a point mutation in its predicted transmembrane domain. Overexpression of the human homologue of neu, the c-erbB-2 gene, in human lung cancer has been reported, and a similar activating point mutation has been suggested. Therefore, we tested for possible aberrations of the c-erbB-2 gene in the region of the transmembrane domain in surgical specimens of human primary lung cancer from 190 patients, and also examined 24 metastases and 26 specimens of noncancerous portions of the lung of the same patients. Single-strand conformation polymorphism analysis of polymerase chain reaction products revealed no point mutations in the target domain in any of these specimens.

Base Sequence↗
PubMed1992

[A study of the defecography].

Defecography, the radiologic examination of the defecation function, has never been reported in Japan, whereas some reports have been published in western countries. However neither the methods nor the criteria for use have been fully established. The author carried out a radiologic study focusing on the maximum lower rectal width and the ano-rectal angle by means of defecography which is considered one of the most efficient methods to examine the morphology and function of defecation. Defecography was carried out in order to study the changes in maximum lower rectal the width and the ano-rectal angle during straining and at rest both with and without the spasmolytic agent, Buscopan. The effects of using different amount of barium sulfate suspension 120 ml and 50 ml were also studied. The maximum rectal width tended to be narrowed and the ano rectal angle to increase during straining as compared to the measurements at rest, while no significant changes, were observed concerning the presence or absence of Buscopan. In comparative studies between pathologic cases such as those with constipation incontinence hemorrhoids and post operative hemorrhoids, and a normal control group, a statistically significant difference was demonstrated only in the cases with hemorrhoids. No difference was demonstrated in any of the cases in association with the use of Buscopan. The length of the anal canal was shortened by straining and was longer in males than in females. Furthermore, by using a catheter with optic fiber, the internal pressure of the anal canal was measured before defecography and it was noted that pressure was lower in older patient and patients with constipation. In conclusion, defecography is one of the most important radiologic examination procedures related to the physio-pathology of defecation.

Adult↗
PubMed1992

Detection of DNA aberrations in human cancers by single-strand conformation polymorphism analysis of polymerase chain reaction products.

We have developed a simple, sensitive method, single-strand conformation polymorphism (SSCP) analysis, to detect a single nucleotide substitution in a DNA fragment amplified and labeled by the polymerase chain reaction (PCR). Mobility shift of single-stranded DNAs due to their specific conformations on non-denaturing polyacrylamide gel electrophoresis can reveal DNA aberrations. By the PCR-SSCP analysis of DNAs from surgical specimens of human cancers, mutated ras genes (17%) and aberrations of tumor suppressor p53 gene (53%) including loss of one of the two alleles and a mutation in the remaining allele were detected in lung carcinomas and aberrations of both of the p53 and retinoblastoma (RB) genes were detected exclusively in advanced hepatocellular carcinomas.

Carcinoma, Hepatocellular↗
PubMed1992

Rearrangement and co-amplification of L-myc and rlf in primary lung cancer.

We have recently characterized a gene fusion and chimeric protein product formed by L-myc and part of a novel gene named rlf in two small-cell lung cancer (SCLC) cell lines. The rlf-L-myc fusion gene is formed by intrachromosomal rearrangements placing the regulatory region and (at least) the first exon of rlf upstream of the L-myc gene. In the characterized cases the fusion gene has also been involved in DNA amplification. Here we report on a similar in vivo rearrangement involving rlf and L-myc in a primary SCLC tumor. In addition, we have found co-amplification of L-myc and rlf without visible rearrangements in either gene in three other SCLC tumors, confirming the physical linkage of these loci.

Blotting, Southern↗
PubMed1992

Effect of nipradilol on cardiovascular hemodynamics during exercise in angina pectoris with old myocardial infarction.

Nipradilol (3,4-dihydro-(2-hydroxy-3-isopropylamino)-propoxy-3-nitroxy-2H-1- benzopyran, K-351, CAS 81486-22-8) is a new type of beta-blocker with vasodilating action. The effect of nipradilol on hemodynamics at rest and during exercise with a multi-stage bicycle ergometer in supine position was studied in 8 male patients suffering from angina pectoris with old myocardial infarction. Nipradilol was orally given at the daily dose of 12 mg (b.i.d.) for one week, and various hemodynamic parameters were measured at rest and during exercise before and after the treatment with nipradilol. At rest, the blood pressure was almost unchanged, heart rate was significantly reduced, cardiac output tended to decrease, and the pulmonary blood pressure and left ventricular ejection fraction (EF) were almost unchanged. At peak exercise, the blood pressure tended to decline, heart rate was significantly reduced, cardiac output tended to decrease and the pulmonary blood pressure and EF increased significantly. Consequently, the antianginal effect of nipradilol is considered to be attributable to the reduction in myocardial oxygen consumption caused by a decrease in double product. It is thus suggested that nipradilol exerts its antianginal effect without adversely affecting the cardiac performance.

Adrenergic beta-Antagonists↗
PubMed1992

[The dura mater adjacent to the attachment of meningiomas: its enhanced MR imaging and histological findings].

The dura mater adjacent to the attachment of meningiomas was enhanced on MR imaging with intravenous Gd-DTPA infusion. It was examined histologically in four patients with intracranial globoid meningiomas. Histological examination revealed that there was no tumor cell invasion within the dura mater enhanced on MR imaging, except at the point of their attachment. A layer of tumor cells was occasionally observed on the surface of the dura mater, but this was limited to within 5 mm of the tumor margin. Our electronmicroscopic observation indicated that enhancement of the dura mater adjacent to the attachment of meningiomas was caused by increased vascular permeability of the dural vessels and extended extravascular space.

Aged↗
PubMed1992

[Electrophysiological identification of the cochlear and vestibular nerves in the cerebellopontine angle: experimental study and clinical implication].

Electrical stimulation was applied on the surface of the eighth cranial nerve in the cerebellopontine angle of dogs and the evoked potentials were recorded with surface electrodes on the scalp. The shape of the evoked potentials recorded was different according to the portion of the nerve stimulated electrically. It was, therefore, possible to precisely identify the nerve stimulated from the surface recorded evoked potentials. This electrophysiological method may be helpful for the surgeon to precisely locate the cochlear and vestibular nerves in various operations in the cerebellopontine angle in human. Our preliminary experience of this monitoring method in acoustic neuroma excision was presented.

Animals↗
PubMed1992

[Prosthetic valve function evaluated by ultrafast computed tomography (Imatron C-100)].

Ultrafast computed tomography (UFCT) is a new diagnostic modality that includes not only imaging of cardiac structures, but also movement of cardiac muscles and valves. It can be useful in the evaluation of prosthetic valves, because the scan time is extremely short and whole cardiac structures are imaged with a slice thickness of 8 mm and within 7 cardiac cycles. We review our experience using UFCT to observe prosthetic valve function in 22 cases with various valvular diseases.

Adult↗
PubMed1992

[A study on relationship between functional sterility and ultrasonographic endometrial images].

By means of vaginal ultrasonography 38 cases with functional sterility were investigated. Ultrasonographic endometrial thickness and texture, along with the maximum follicle diameter, serum estradiol and progesterone levels were measured in connection with the outcome of treatment for sterility. Endometrial texture was classified into 4 types: even-hypoechoic (P1) and mixed (P2) in late proliferative and even-echogenic (S1) and mixed (S2) in mid-secretory phases. Histological findings were also compared with ultrasonographic images and the following results were obtained. 1. Endometrial thickness and outcome of sterility. 1) Endometrial thickness in mid-proliferative and mid-secretory phases was 9.7 +/- 1.4 mm (mean +/- SD) and 13.9 +/- 1.7, respectively, in a group with good prognosis, while it was 6.7 +/- 1.8 and 10.1 +/- 2.2 in a poor prognosis group. The endometrium was significantly thinner in the latter group than in the former (p less than 0.05). 2) No. difference was found in estradiol, progesterone levels or the maximum diameter of the follicle. 2. Endometrial texture and outcome of sterility. 1) The outcome was identical in both groups whether the endometrium in late proliferative phase was of the even-hypoechoic or of the mixed type. 2) In the mid-secretory phase, comparison of patients where endometrium was of the even-echogenic type (S1) with those who had the mixed type (S2), revealed clearly poorer prognosis in the latter (p less than 0.05). 3) Serum estrogen and progesterone levels were not significantly different in any endometrial patterns and no connection was found between endometrial textures and the hormonal levels. 3. Histological findings in cases where mixed pattern endometrium was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Endometrium↗
PubMed1992

[Five cases of intracranial lipoma; CT and magnetic resonance images].

We encountered five cases of intracranial lipoma after introduction of MRI. They were located in the quadrigeminal plate, interpeduncular fossa, pineal region and two of them were found in the cerebellopontine angle, (although intracranial lipoma in this location has been reported to be extremely rare). MRI can precisely locate a small lesion that would be overlooked by CT scans. Operative treatment was performed in two symptomatic cases (CP angle and pineal lesions) and the tumors were subtotally resected. The symptoms of the patients disappeared postoperatively. This indicated that even subtotal removal can alleviate the symptoms of intracranial lipomas and that favorable results can be obtained.

Adult↗
PubMed1991

p53 gene mutations in gastric cancer metastases and in gastric cancer cell lines derived from metastases.

Structural alterations of the p53 gene were investigated in tissue specimens of gastric and cervical cancers and in cell lines of gastric, esophageal, and cervical cancers, by polymerase chain reaction-single-strand conformation polymorphism analysis. Two of the four gastric cancer metastases and four of the eight cell lines originally established from gastric cancer metastases were found to have p53 gene alterations in the exon 5 to 11 region; point mutations and amino acid replacements were detected in a liver and an ovary metastasis at exon 7, in the TMK1 and MKN1 cell lines at exon 5, and in the OKAJIMA cell line at exon 10. The normal allele was not found in these cell lines. In the KATO-III cell line, gross deletion and rearrangement of the p53 gene were noted. However, no p53 mutations were identified in 19 primary lesions of gastric cancer, suggesting that the p53 gene abnormality preferentially occurs in the advanced stages of gastric cancer. In contrast to the gastric cancer, none of the 13 esophageal cancer cell lines, including two cell lines established from metastases, and none of the four cervical cancer cell lines showed any aberration in exons 5 to 11 of the p53 gene. During the course of the study, a novel polymorphism in intron 7 of the p53 gene was found, which can be recognized by restriction enzyme digestions of the polymerase chain reaction product.

Amino Acid Sequence↗