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Biomedical subjects

Y Kawase

Publications and source records attributed to Y Kawase.

At least 19 recordsLinked to original sources
PubMed1992

Construction and characterization of a fusion protein with epidermal growth factor and the cell-binding domain of fibronectin.

An efficient expression system was constructed for C-EGF, a fusion protein made of a fragment of the cell-binding domain of human fibronectin (FN) bound with epidermal growth factor (EGF). C-EGF was produced in Escherichia coli HB101 cells carrying the recombinant plasmid pCE102 as inclusion bodies, which were solubilized and refolded after purification. C-EGF had both cell-adhesive and EGF activities, so it might be more effective than EGF in therapeutic applications. This fusion system would be useful for the construction of a recombinant drug delivery system for cells that have fibronectin receptors (integrins).

Cell Adhesion↗
PubMed1992

Biochemical studies on oral toxicity of ricin. V. The role of lectin activity in the intestinal absorption of ricin.

In order to investigate a possible role of lectin activity of ricin in its absorption from the small intestine, we prepared two ricin derivatives. BMH-ricin, prepared by crosslinking A and B chains of ricin with 1,6-bismaleimidohexane, was nearly non-toxic but the lectin activity was unaltered. And, NBS-ricin, prepared by the oxidation of tryptophanyl residues of ricin with N-bromosuccinimide, was not only non-toxic but also non-lectinic. After the oral administration of ricin derivatives to rats, their interaction with the digestive tract and absorption into the circulatory systems have been compared with those of ricin, immunochemically and histologically. It was shown by immunostaining that ricin and BMH-ricin could bind to the intestinal mucosa, whereas NBS-ricin could not. No appreciable damage in the small intestine from rats treated with either BMH-ricin or NBS-ricin has been observed, in contrast to ricin treatment where severe impairment of the small intestinal tissues resulted after 5 h. Immunoreactive ricin in the liver has been determined with the ricin enzyme immunoassay (EIA). When compared at 48 h after oral administration, NBS-ricin was not detected, whereas BMH-ricin was found to be 38 micrograms/liver and ricin 100 micrograms/liver. From these results, it was inferred that the lectin activity of ricin plays an important role in the absorption of ricin from the small intestine and that the absorption of ricin protein was enhanced by its high toxicity.

Administration, Oral↗
PubMed1991

NMR studies for identification of dI:dG mismatch base-pairing structure in DNA.

One- and two-dimensional NMR experiments have been undertaken to investigate deoxyinosine:deoxyguanosine (dI:dG) base pairing in a self-complementary dodecadeoxyribonucleotide, d(C1-G2-C3-I4-A5-A6-T7-T8-G9-G10-G11-G12) (designated IG-12), duplex. The NMR data indicate formation of a dI(syn):dG(anti) base pair in a B-DNA helix. This unusual base pairing results in altered NOE patterns between the base protons (H8 and H2) of the I4 residue and the sugar protons of its own and the 5'-flanking C3 residues. The dI(syn):dG(anti) base pair is accommodated in the B-DNA duplex with only a subtle distortion of the local conformation. Identification of the dI:dG base pairing in this study confirms that a hypoxanthine base can form hydrogen-bonded base pairs with all of the four normal bases, C, A, T, and G, in DNA.

Base Composition↗
PubMed1991

Similarity of expression of low molecular weight G proteins smg p21A and ras p21 in normal and malignant human tissues.

We prepared monoclonal antibodies specific for smg p21A, one of the low molecular weight GTP-binding proteins and possibly a suppressor molecule for ras p21. Two monoclonal antibodies (T22 and T212) reacted with smg p21A but not with Ki-ras p21, both of which were produced by Escherichia coli. These two clones detected an Mr 21,000 band in one-dimensional immunoblotting of extracts of a human pancreatic cancer cell line which was indistinguishable from a band detected by RASK-3, a monoclonal antibody specific for ras p21. However, T22 and T212 detected a single spot in two-dimensional immunoblotting that was clearly different from the three spots detected in the same cellular extracts by RASK-3. A series of normal and malignant human tissues were examined for the expression of smg p21A and ras p21 by immunohistochemical methods utilizing T22 and RASK-3. In essentially all tissues examined, both normal and malignant, smg p21A and ras p21 were expressed with great similarity. Expression of both molecules in all malignant tissues examined was coincident with that in normal tissues except that gastric cancer showed increased expression of the two molecules in comparison with normal gastric tissue.

GTP-Binding Proteins↗
PubMed1991

NMR studies of a DNA containing 8-hydroxydeoxyguanosine.

The effects of hydroxylation at the C8 of a deoxyguanosine residue in DNA were studied by NMR analysis of a self-complementary dodecanucleotide, d(C1-G2-C3-oh8G4-A5-A6-T7-T8-C9-G10-C11-G12), which has an 8-hydroxy-2'-deoxyguanosine (oh8dG) residue at the 4th position. NMR data indicate that the 8-hydroxyguanine (oh8G) base takes a 6,8-diketo tautomeric form and is base-paired to C with Watson-Crick type hydrogen bonds in a B-form structure. The thermal stability of the duplex is reduced, but the overall structure is much the same as that of the unmodified d(CGCGAATTCGCG) duplex. The structural changes caused by 8-hydroxylation of the deoxyguanosine, if any, are localized near the modification site.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1991

Role of type III homology repeats in cell adhesive function within the cell-binding domain of fibronectin.

Recombinant fibronectin (FN) fragments and their mutant proteins were produced to elucidate the role of type III homology repeats in cell adhesive activity within the cell-binding domain of FN. Cell adhesive activity of the 11.5-kDa fragment, the cell attachment site of the cell-binding domain, was less than 0.1% that of native FN despite the presence of the Arg-Gly-Asp-Ser sequence. The activity increased as type III homology repeats were added to the N terminus of the 11.5-kDa fragment, and a 52-kDa fragment with four additional type III repeats had almost the same activity of native FN. Deletion of Arg-Gly-Asp from the fully active fragments completely abolished the cell adhesive activity. Deletion of one or two repeats from the 52-kDa fragment affected the extent of the cell adhesive activity, the degree of the effect being inversely correlated with the distance of the deletion from the type III repeat containing Arg-Gly-Asp-Ser. Rearrangement of type III repeats caused much loss of activity. These results suggest that the number and kinds of type III repeats and their correct alignment rather than the putative synergistic site decide the extent of the specific cell adhesive activity.

Amino Acid Sequence↗
PubMed1991

Tolerogenic ability of thymocytes in organ-cultured thymus lobes.

It is generally believed that macrophages and dendritic cells are the major cell populations that present tolerogenic self antigens to developing thymocytes. However, it is still controversial whether self antigens expressed on thymocytes themselves work as tolerogens in the thymus. To evaluate this possibility, Thy-1 bright cells were sorted out from fetal thymus cells on the 15th gestation day, and were colonized into 2'-deoxyguanosine-treated allogeneic thymus lobes. The repopulated thymus lobes were organ-cultured, and the allo-specific killer activity of thymocytes recovered from the lobes was examined. These cells were tolerant to class I but not to class II-MHC of the donor haplotype, indicating that class I molecules expressed on the thymocytes worked as tolerogen. Tolerogenic ability of Thy-1+ cells was also demonstrated in another system. Upon intimate contact with allogeneic thymus lobes on a polycarbonate filter, thymus lobes fused with each other and Thy-1+ cells co-migrated (Eur. J. Immunol. 19:1525-1530, 1989). In thymus lobes rendered parabiotic from day 5, CTL tolerance was achieved against class I but not to class II MHC. These data indicate that thymocyte-thymocyte interaction is sufficient to induce class I CTL tolerance in developing thymocytes.

Animals↗
PubMed1991

Heat transfer in bubble column and airlift bioreactors: Newtonian and non-Newtonian fermentation broths.

A theoretical model has been developed for heat transfer in bubble column and airlift bioreactors, which is applicable for Newtonian and non-Newtonian fermentation media. The proposed model is based on a similarity between heat transfer in gas-sparged pneumatic reactors and turbulent natural convection. The applicability of the proposed model was discussed using a wide range of experimental data, and good agreement was obtained.

Biotechnology↗
PubMed1991

Early gastric cancer arising from localized Ménétrier's disease.

A case of early gastric cancer arising from Ménétrier's disease in the stomach is described. The patient was a 53-year-old man, who suffered from epigastralgia. Radiological and endoscopic examination demonstrated giant mucosal folds along the greater curvature of the stomach. On the distal margin, signet-ring cell carcinoma was demonstrated by biopsy. The coexistence of Ménétrier's disease and early gastric cancer has rarely been reported. Cases reported in the literature were reviewed and the increased malignant potential of Ménétrier's disease was discussed.

Adenocarcinoma↗
PubMed1991

Production and characterization of functional domains of human fibronectin expressed in Escherichia coli.

An efficient expression system was constructed in Escherichia coli that produced a 33-kDa fragment, C-274, of human fibronectin with a strong cell-adhesive activity. The entire sequence of the heparin-binding domain with 271 amino acids, H-271, was also expressed. Deletion analysis of the type III repeats showed that the heparin-binding site was at type III-13. The cell-adhesive activity of a fusion protein, CH-271, containing the cell- and the heparin-binding domains was twice that of C-274 when BHK but not B16-F10 melanoma cells were tested; H-271 alone was inactive. Recombinant proteins containing the CS1 sequence of the IIICS region were more active than C-274 and CH-271 with B16-F10. However, H-296, which contained both H-271 and CS1, was almost inactive with BHK. CH-296, which contained CS1 at the C-terminus of CH-271, was more active with B16-F10 than H-296 and C-CS1, which was produced by the deletion of H-271 from CH-296. Thus, the cell-binding domain was active with both kinds of cells. The heparin-binding domain promoted the adhesion of both kinds of cells only when linked to the cell-binding domain or CS1. CS1 was specific for the adhesion of B16-F10 but was not essential.

Animals↗
PubMed1991

[Symptomatological rubral tremor caused by vertebral-basilar artery embolism].

Rubral tremor is a distinct clinical entity as described by Gorden Holmes. We have reported here a 44 years old woman with rubral tremor appearing about 2 months after an embolic attack of vertebral-basilar artery. On neurological examination there were left homonymous hemianopsia, dysarthria very mild weakness of left upper and lower limbs with clumsiness of her left lower limb and the tremor of the left upper limb. Muscle tone was increased in her left upper limb with dystonic posturing. The tremor of her left upper limb was present at rest with regular rhythm of 2.8 Hz. This tremor included the reciprocal movements such as radial and ulnar flexion of the left wrist and independent movements of different fingers. It was accentuated by postural adjustment and by guided voluntary movements and disappeared during sleep. Surface EMG demonstrated that the grouping discharge was seen not only alternatingly but also synchronously between agonists and antagonists. A brain MRI image revealed multiple lesions including right thalamus and left cerebellum. No lesions were detected in brain stem. On the basis of MRI, it was questionable whether the lesion involved the dentate nucleus in the left cerebellum although the lesion was located at the medulla near the dentate nucleus extending from the cortex. So-called rubral tremor could be generated in lesions of cerebello-rubro-thalamic system without rubral lesion itself.

Adult↗
PubMed1991

Analysis of nucleic acids by ion-spray mass spectrometry.

We analyzed various synthetic oligonucleotides with the use of ion-spray mass spectrometer. The most suitable conditions were investigated for analyzing oligonucleotides with molecular weights ranging from 3000 to 15000. We have found that the pH of the solvent was critical to reduce the formation of adduct ions in the mass spectra. Tandem mass spectrometry was also used to study the sequences.

Base Sequence↗
PubMed1990

Modulation of haptotactic migration of metastatic melanoma cells by the interaction between heparin and heparin-binding domain of fibronectin.

We utilized recombinant fibronectin polypeptides with cell-binding domain and heparin-binding domains (referred to as C-274 and H-271, respectively) and their fusion polypeptide (CH-271) to examine the role of sulfated polysaccharide heparin and/or the functional domains of fibronectin in modulating tumor cell behavior. Both C-274 and CH-271 polypeptides with cell-binding domains promoted the adhesion and migration of B16-BL6 melanoma cells, whereas H-271 did not. Heparin bound to the immobilized polypeptides with heparin-binding domain (H-271, CH-271, and a mixture of C-274 and H-271 or fibronectin) but did not affect the tumor cell adhesion to the substrates. At the same time, heparin or two monoclonal antibodies against the heparin-binding domain were able to inhibit the haptotactic migration to CH-271 or fibronectin, though not to C-274 or a mixture of C-274 and H-271. This suggests that although heparin did not affect tumor cell adhesion to the cell-binding domain near the heparin-binding domain in CH-271 or fibronectin, it did lead to a modulation of cell motility. It seems likely that the regulatory mechanism may depend on interaction between heparin-like molecules on the cell surface and the heparin-binding domain in fibronectin, rather than on simple steric hindrance or on the masking of the cell-binding domain caused by the binding of heparin to heparin-binding domain.

Animals↗
PubMed1990

Inhibition of lung metastasis by synthetic and recombinant fragments of human fibronectin with functional domains.

We have investigated the antimetastatic effect of synthetic or recombinant peptides containing the functional domains of fibronectin on experimental and spontaneous lung metastases of murine tumor cells. CS1 peptide which is present within type III homology connecting segment (IIICS) as well as C-274 (cell-binding domain) were able to inhibit experimental lung metastasis when co-injected intravenously (iv) with B16-BL6 melanoma cells, while H-271 (heparin-binding domain) could not. In the spontaneous metastasis model, multiple iv administrations of CS1 or C-274 after surgical excision of primary tumors caused a significant reduction of metastatic colonies in the lung. Both CS1 and C-274 significantly inhibited cell adhesion and migration to fibronectin-coated substrates when added freely in solution. CS1 peptide also inhibited the cell adhesion and migration to laminin-coated substrates, but C-274 did not. H-271 did not have any inhibitory effect on cell adhesion or migration to either of the substrates. Similarly, CS1 inhibited tumor invasion to both Matrigel/fibronectin- and Matrigel/laminin-coated filters, whereas C-274 inhibited the invasion to only Matrigel/fibronectin-coated filter. These results indicate that CS1 peptide of fibronectin, lacking the Arg-Gly-Asp-containing domain, actively inhibits tumor metastases in spontaneous and experimental metastasis models. The use of such a peptide might offer a promising therapeutic approach for combatting or preventing cancer metastasis.

Amino Acid Sequence↗
PubMed1990

The effect of ionizing radiation on epidermal Langerhans cells--a quantitative analysis of autopsy cases with radiation therapy.

Langerhans cells (LCs) are dendritic cells located in the epiderm is with antigen-presenting capacities. We performed a quantitative analysis of LC density in the anterior chest skin of 286 autopsy cases, including 31 cases treated with radiation therapy. Skin specimens were stained by immunoperoxidase technique (PAP method) with an anti-S-100 protein antiserum. S-100 positive LCs were counted for comparison between non-irradiated and irradiated cases. In this study we noted that, 1) The decline in density of the LCs was age-related and dendritic processes were more prominent in younger groups. 2) The cases irradiated within one month before autopsy showed a reduction in LC density compared with age-matched controls. 3) The cases irradiated more than one month before autopsy demonstrated no consistent or definite tendency. It is suggested that ionizing irradiation as well as ultraviolet light may deplete the LC density in an acute phase. The possibility that radiation therapy alters immunological surveillance in the human skin is discussed.

Adolescent↗
PubMed1990

[Perfusion study of the pulmonary hilar region by SPECT--normal cases].

Alveoli in the hilar region comprise the peripheral area containing daughter branches from subsegmental or one more divisional peripheral bronchi. Pulmonary perfusion in hilar region was examined by SPECT (single photon emission CT) in ten normal volunteers. ROI (region of interest) in the axial images were set in the hilar region, the upper, middle and lower lung fields with 10.8 mm thickness. Counts/one pixel (C/P) were calculated in these ROI. There was a tendency of C/P increase from upper to lower lung field. And there were no significant differences in C/P increase between hilar region and other axial fields. In the chronic obstructive pulmonary diseases, however, ventilation studies in the previous reports using Xe dynamic CT or PET (positron emission tomography) showed differences between outer region and hilar region. This method will be expected to evaluate the pulmonary perfusion not only in the whole lung but in different lung areas, including the hilar region in the chronic obstructive pulmonary diseases.

Adult↗