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K Shiokawa

Publications and source records attributed to K Shiokawa.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Studies on factors influencing the attack of subarachnoid hemorrhage during labor].

We analyzed factors affecting attacks of subarachnoid hemorrhage (SAH) retrospectively in 411 patients and studied the relation of the attacks with labor. The onset time of SAH has two peaks of the time: one is 7:00 a.m. and the other is between 16:00 and 17:00 in the afternoon. The attacks of SAH during labor were observed in 15.1% of all the patients. It was noted that 66.7% of all the attacks were observed at the time with certain external stress such as working, sporting, sexual intercourse, etc. The number of patients who suffered from attacks during labor with history of hypertension and insomnia were not significantly different compared with those suffered from attacks during other activities, but 40-59 aged men those who have a history of smoking were significantly more in number compared with those that suffered attacks during other activities. Transient increase of blood pressure due to external stress is suggested as an initiative factor of the bleeding during working. Reactivity of the individuals against physical and mental stress (external stress) might be considered to be the major problem, although it remains not to be unexplained whether labor itself participates in the onset of SAH. Regarding the prevention of SAH during labor, new methods of medical examination and health control is required.

Adult↗
PubMed1994

Molecular cloning of cDNA for XTCAD-1, a novel Xenopus cadherin, and its expression in adult tissues and embryos of Xenopus laevis.

We have isolated from a Xenopus tailbud cDNA library a novel cadherin cDNA, denoted as XTCAD-1, which contained an open reading frame including the entire coding region. XTCAD-1 codes for 714 amino acids (molecular mass: 96 kDa), which include five characteristic extracellular cadherin motifs, a single putative transmembrane domain, and a cytoplasmic domain. In each domain, XTCAD-1 shared extensive homologies with other cadherins, and was related to EP-, E-, and P-cadherins more closely than to N- and M-cadherins. In adult Xenopus, XTCAD-1 mRNA was strongly expressed in intestine/stomach, kidney and skin, which are respectively derived from endoderm, mesoderm, and ectoderm. In Xenopus embryogenesis, expression of XTCAD-1 mRNA was first detected at blastula stage, and the level of the expression increased gradually during gastrula stage, reached a peak at tailbud stage and then decreased slightly at tadpole stage. These results suggest that in Xenopus laevis XTCAD-1 plays an important role in the maintenance of adult tissues that contain epithelial cells abundantly and also in morphogenesis in early embryonic development.

Amino Acid Sequence↗
PubMed1994

Structural characterization of porcine enteropeptidase.

Enteropeptidase (EC 3.4.21.9) is a key enzyme in the intestinal digestion cascade responsible for the conversion of trypsinogen to trypsin, which then activates various pancreatic zymogens. In order to structurally characterize the enzyme, we purified the enzyme from porcine duodenal mucosa and showed that it consists of three polypeptide chains, which we named "mini" chain (M chain), light chain (L chain), and heavy chain (H chain) in order of increasing molecular size. Based on their NH2-terminal sequences, a cDNA clone for porcine enteropeptidase was isolated and analyzed. The clone was 3597 base pairs long, which encoded 1034 amino acid residues of a single-chain precursor form of enteropeptidase. The precursor contained an additional NH2-terminal 51-residue sequence including a putative internal signal sequence, followed by the M chain (66 residues), the H chain (682 residues), and the L chain (235 residues) in that order. The H chain had regions partially homologous in sequence with low density lipoprotein receptor and complement components. On the other hand, the L chain was highly homologous with the catalytic domains of trypsin-like serine proteinases. The structural model of the L chain suggests that the sequence, Arg885-Arg-Arg-Lys888, is probably involved in the unique substrate specificity of the enzyme, preferring acidic amino acid residues at the P2-P5 sites.

Amino Acid Sequence↗
PubMed1994

Cloning of a brain-type aldolase cDNA and changes in its mRNA level during oogenesis and early embryogenesis in Xenopus laevis.

A full length cDNA clone (cXALD3) for Xenopus laevis aldolase mRNA, which exists abundantly in oocytes, was isolated from Xenopus laevis ovary cDNA library, and its nucleotide sequence was determined. The cDNA was 1.8 kb in length and encoded 363 amino acids. From the deduced amino acid sequence and the Northern blot analysis of the RNAs from several adult tissues, this clone was concluded to be a brain-type aldolase gene. The XALD3 mRNA level per egg or embryo was high during early oogenesis, but was markedly reduced during late oogenesis and was maintained at low level during early embryogenesis until it started to increase at the late neurula stage. The mRNA was also detected in testis. The characteristic change in the temporal pattern of expression and the distribution of XALD3 mRNA among different tissues suggest a possibility that brain type aldolase may play some important roles in gametogenesis and in neurulation.

Amino Acid Sequence↗
PubMed1994

Fetal rat glandular stomach epithelial cells differentiate into surface mucous cells which express cathepsin E in the absence of mesenchymal cells in primary culture.

It is well established that the differentiation of glandular stomach epithelial cells is affected by many factors including epithelial-mesenchymal interactions. To clarify the control mechanism of their differentiation, we developed a primary culture system for fetal rat glandular stomach epithelial cells, and examined their differentiation in the absence of mesenchyme. Pure glandular stomach epithelial tissues obtained from 16.5-day fetal rats proliferated rapidly, increasing their number about 20 times in the first 7 days. The epithelial nature of the cells was confirmed by the presence of cytokeratin in the cells. Glandular stomach epithelial cells formed simple cuboidal/squamous epithelia with many mucous granules in their cytoplasm, and exhibited epithelial polarity with microvilli on the luminal surface, basal lamina-like material on the basal surface, and junctional complexes in the apical region. Biochemical analysis showed that the cells expressed acid protease activity in culture. Previous studies showed that glandular stomach epithelial cells specifically expressed two types of acid proteases: pepsinogens in chief and mucous neck cells, and cathepsin E in surface mucous cells. Immunohistochemical studies using specific antibodies showed that the cultured cells expressed cathepsin E but not pepsinogens, and the result was confirmed by zymogram and Western blotting analysis. We thus concluded that fetal rat glandular stomach epithelial cells differentiated into surface mucous cells that expressed cathepsin E in primary culture in the absence of mesenchyme.

Animals↗
PubMed1994

Developmental changes of DNA methylation pattern of embryonic chick pepsinogen gene.

Embryonic chick pepsinogen (ECPg) is one of the pepsinogen isozymogens and its expression is restricted to epithelial cells of the embryonic chick proventriculus (glandular stomach). To examine whether DNA methylation is involved in the regulation of organ-specific and developmental stage-specific expression of ECPg gene, we analyzed the extent of methylation of ECPg gene in normal embryonic and hatched chick organs using methylation-sensitive restriction enzymes. In the proventriculus some CCGG sites underwent demethylation in the gene region after the onset of transcription of the ECPg gene. By contrast, these sites were kept methylated throughout the development in the other organs which do not express ECPg gene. GCGC sites in the gene region became methylated in organs which do not express the ECPg gene, after the initiation of transcription of the ECPg gene in the proventriculus. In the proventriculus, GCGC sites, which were methylated in other organs, were kept unmethylated throughout the development. The methylation state of CpG sites showed no change in the proventriculus of a chick 2 weeks after hatching when the expression of the ECPg gene had completely ceased. The data presented here demonstrate that the DNA methylation is involved in the regulation of organ-specific expression, but stage-specific expression might be brought about by some other mechanisms.

Animals↗
PubMed1994

Mesenchymal regulation of epithelial gene expression in developing avian stomach: 5'-flanking region of pepsinogen gene can mediate mesenchymal influence on its expression.

The expression of a gene encoding an embryonic chick pepsinogen was investigated in developing avian gut. Expression is restricted to the epithelial layer of the embryonic proventriculus (glandular stomach). We can therefore regard this gene as a marker gene for proventricular epithelial differentiation. There is some considerable evidence in favour of epithelial-mesenchymal interactions being important during the development of the gastrointestinal system; for example, pepsinogen expression is induced in proventricular and gizzard (muscular stomach) epithelial by the proventricular mesenchyme but is suppressed by the gizzard mesenchyme. In the present paper, we studied how the mesenchymes influence this gene expression pattern. For this we produced constructs containing various portions of the 5'-flanking region of the embryonic chick pepsinogen gene, driving reporter sequences (beta-galactocidase or luciferase), and these constructs were transfected into dissociated epithelial cells either from the proventriculus or gizzard. We then recombined these cells with mesenchymal cells and cultured them as cell aggregates. In this way, we were able to dissect the timing and other requirements of the epithelial-mesenchymal interactions for expression of embryonic chick pepsinogen gene. We also report that 1.1 kb of 5'-flanking sequence is sufficient to drive correct expression of embryonic chick pepsinogen gene, although further enhancement was seen if the constructs contained 3.2 kb of upstream sequence.

Animals↗
PubMed1994

Temporal control of gene expression from endogenous and exogenously-introduced DNAs in early embryogenesis of Xenopus laevis.

We review here our studies on temporal control of the expression of genes in zygotic nucleus and of exogenously introduced genes in Xenopus embryos. For zygotic gene expression, our studies have revealed that mRNA synthesis, tRNA synthesis and rRNA synthesis initiates at the cleavage stage, MBT stage and late blastula stage, respectively. We also briefly summarize here results of the effects of weak bases on rDNA expression, nucleo-cytoplasmic transport and polysomal mobilization of newly-synthesized RNAs. For exogenously injected genes expression our data have shown the control of the expression by the promoter and configuration (circular or linear) of the injected DNAs but not necessarily by cellular changes that take place during the midblastula transition (MBT).

Animals↗
PubMed1993

Molecular cloning of cDNAs for two Xenopus proteasome subunits and their expression in adult tissues.

Proteasome, a large protein complex with ATP-dependent protease activities, is composed of non-identical but closely related multi-subunits. Using cDNAs for rat proteasome subunits as probes, we obtained three cDNA clones for two Xenopus proteasome subunits from ovary cDNA library. The primary structures of the three cDNAs showed high homology to the corresponding proteasome subunits of other mammalian species (above 90%) and also considerable homology to those of Drosophila and yeast. These results indicate that the sequences of proteasome subunits are well conserved during evolution. Northern blot hybridization revealed that RNAs for the newly isolated subunits (XC8 and XC9) and the previously isolated subunit (XC3) occur at very high levels in testis and ovary, at moderately high levels in lung, skin kidney and spleen, and at low levels in liver, stomach and muscle. It was also shown that relative amounts of the mRNAs for the three subunits are similar in all the adult tissues examined. From these results, we concluded that the expression of the genes for the three subunits (XC3 XC8 and XC9-1) takes place in a roughly coordinated manner in different adult tissues.

Amino Acid Sequence↗
PubMed1993

Cleavage arrest in Xenopus embryos injected with a human c-myc gene.

The c-myc protein has been implicated in cell proliferation and differentiation of various cell lines, but its function in early embryos of Xenopus is obscure. We introduced the c-myc gene into embryos using a pcDL-SR alpha plasmid with an efficient promoter of the gene. It was found that fertilized eggs injected with the c-myc gene were arrested at the 4-cell stage within 1 h of the injection, when the plasmid that carried c-myc gene but not the plasmid that carried defective c-myc gene was injected. These results also suggest that Xenopus embryos already have the ability to transcribe an exogenously injected c-myc gene at the 4-cell stage.

Animals↗
PubMed1993

Initiation of DNA synthesis in a high molecular weight fraction of Xenopus egg extract.

Xenopus egg extract was fractionated by gel-filtration column chromatography and DNA synthetic activity was examined using double-stranded DNA as a template. The major activity eluted had an apparent molecular mass of about 300 kDa. Product analyses showed that de novo DNA synthesis occurs with formation of replication bubbles, thereby suggesting that this fraction catalyzes the initiation of DNA replication. Activities of DNA polymerase alpha-primase and DNA helicase overlapped with the DNA synthetic activity, but the elution profiles of the enzymes differed from that of the DNA synthetic activity. Therefore, this 300-kDa fraction may contain a component which differs from the above enzymes yet is essential for initiation of DNA replication.

Animals↗
PubMed1993

[Dynamic roles of the upper extremity during axillary crutch gait].

To ambulate successfully with an axillary crutch, the upper extremities play an important part in supporting the body's entire weight. To evaluate the roles of the upper extremity during axillary crutch gait 15 normal adult subjects, 23 patients with an affected single leg, and 3 patients with rheumatoid arthritis (RA), were investigated. The gait patterns using crutches were: the one-leg swing-through crutch gait and three-point crutch gait for both normal subjects and patients with an affected single leg, and the three-point crutch gait for RA patients. The real-time motion analysis system "Quick-MAG", force plates, and a VTR system were used for data acquisition. The forces at the arm-pit and the hands during the swing-through crutch gait decreased when the cadence increased from 60 to 100 steps per minute. However, the floor reaction curve suggested distortion of the rubber at the crutch tip when the cadence reached 100. In the plane of progression during the crutch stance phase, the elbow flexion angle was about 14 degrees, and the wrist radial flexion angle about 23 degrees in the middle of the crutch stance phase. This position might be the best for efficient force exertion from the upper extremity. The unloading ratio during the three-point crutch gait was 35 percent in the normal subjects, 49 percent in patients with an affected single leg, and 14 percent in the RA patients. The results of the unloading ratio, indicated that elbow and wrist joint impairment prevented the RA patients from sustaining enough posture to support body weight during the three-point crutch gait.

Adolescent↗
PubMed1993

[Two cases of giant aneurysms arising from the distal segment of the anterior cerebral circulation].

Giant aneurysm arising from the distal segment of the anterior cerebral circulation is extremely rare, and only 14 cases of anterior cerebral circulation aneurysms have been reported in the literature. This report describes two cases of giant intracranial aneurysms, one arising from the distal segment of the middle cerebral artery, and the other from the azygos anterior cerebral artery. Although both of the patients started with intracranial hemorrhage, their surgical outcomes were good. The growth mechanisms of each aneurysm are discussed based on the clinical and pathological findings. Since the wall of the middle cerebral artery aneurysm showed granulomatous changes with infiltration of many inflammatory cells, the aneurysmal enlargement is considered to have resulted from chronic inflammation of the wall. In the case of anterior cerebral artery aneurysm, hemodynamic stress through the azygos artery may have caused the giant aneurysm. Operative indication for giant intracranial aneurysm is controversial. Since the surgical outcomes of reported cases are definitely better than those of the patients with proximal giant aneurysm, we conclude that giant aneurysm arising from the distal segment of the cerebral artery should be treated surgically.

Adult↗
PubMed1992

Induction of differentiation of the human promyelocytic cell line HL-60 by activin/EDF.

A human promyelocytic cell line, HL-60, treated with activin/EDF was found to differentiate into monocyte/macrophage-like cells. This was shown not only by morphology but by the loss of myeloperoxidase granules and the appearance of nonspecific esterase. Dose-dependent inhibition of the differentiation by follistatin, an activin-binding protein, confirmed that it was indeed caused by activin. Thus, activin/EDF exerts its effect on hematopoietic cells not only on erythroid differentiation but also on at least a part of myeloid cell differentiation.

Activins↗
PubMed1992

Expression pattern of the activin receptor type IIA gene during differentiation of chick neural tissues, muscle and skin.

To elucidate target cells of activins during embryogenesis we isolated cDNAs of chick activin receptor type II (cActR-II) and studied expression patterns of the cActR-II gene by in situ hybridization. Transcripts of cActR-II were observed in neuroectoderm developing to spinal cord, brain and eyes, in surface ectoderm differentiating to epidermis, and in myotomes differentiating to muscles. The expression patterns of cActR-II suggest that activin and its receptor are involved in differentiation of chick neural tissues, muscle and skin after inducing the dorsal mesoderm.

Activin Receptors↗
PubMed1992

Isolation and characterization of a Xenopus cDNA which encodes a homeodomain highly homologous to Drosophila Distal-less.

A novel homeobox gene of Xenopus was isolated from the ovary cDNA library. The homeodomain of the encoded protein was homologous to that of Drosophila Distal-less (Dll), and the gene was termed Xdll. The mRNA exists in a large amount in ovary, and in a small amount in testis, but was not detected in muscle, kidney, gut, and liver. The mRNA also occurs in a large amount in oocytes and is maintained in unfertilized eggs and cleavage stage embryos as a maternal mRNA at a low but distinctly detectable level. The amount of the mRNA per embryo increases gradually in later stages by zygotic expression. Embryo dissection experiment revealed that the transcript is abundant in the anterior region at the neurula stage, suggesting that Xdll may play a role in the establishment of the structures in the anterior part of the embryo.

Amino Acid Sequence↗