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K Egawa

Publications and source records attributed to K Egawa.

At least 91 records · Page 5Linked to original sources
PubMed1993

Co-expression of mutant and normal human insulin receptors in COS 7 cells.

In order to assess the interference of the mutant insulin proreceptor on normal receptor function and formation of proreceptor-receptor heterotrimers (alpha beta-proreceptor), COS 7 cells were transfected with the same amount of expression plasmid (pGEM3SV) containing wild-type, a mutant proreceptor cDNA and both, using the DEAE-dextran method. Scatchard analysis of insulin binding data revealed that there was an approx. 50-fold higher receptor concentration in the transfected cells than in untransfected cells. After 0.025% trypsin treatment, insulin binding to the cells expressed with wild-type, proreceptor and both increased by 1-fold, 2.9-fold and 1.5-fold of the untreated cells, respectively. In the presence of 167 nM insulin, the amounts of phosphate incorporated into the 95 kDa protein beta-subunits and 210 kDa proreceptors from co-transfected cells, were identical to those of an in vitro mixture of the wild-type and the mutant receptors. At 10 nM insulin, the proreceptors from co-transfected cells normally autophosphorylated by insulin stimulation, whereas those mixed in vitro did not (73.3 +/- 9.3 vs. 29.6 +/- 2.6% of the maximal effect, n = 4, P < 0.01). However, at a similar concentration of insulin, the phosphate incorporation into Glu-80/Tyr-20 polymers by receptors from co-transfected cells was decreased when compared with a in vitro mixture (9.0 +/- 2.6 vs. 22.5 +/- 6.7% of the maximal effect at 4 nM, n = 6, P < 0.01), although the basal and maximally stimulated phosphate incorporation were comparable among these groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Different effects of substitutions at residues 224 and 228 of MHC class I on the recognition of CD8.

Previous studies indicated that weak xenoresponse to HLA class I by mouse T cells is due to the inefficient interaction of mouse CD8 with the alpha 3 domain of HLA class I. The present study using chimeric H-2Kb molecules with recombinant alpha 3 domain between H-2Kb and HLA-B7 as well as single amino acid mutants of H-2Kb demonstrated that each substitution at residues 224 and 228 affects recognition of CD8-dependent mouse CTL clones. On the other hand, reactivity of IL-2-producing H-2Kb-specific T cell hybridoma transfected with mouse CD8 alpha was abrogated by substitution at residue 224 but not by that at residue 228. This indicates that the substitution at residue 228 affects recognition of CD8-dependent CTL but does not critically affect binding of CD8 to MHC class I molecules, although residue 224 abrogates binding of CD8. The model structure of the alpha 3 domain of H-2Kb suggests that the substitution at residue 224 induces conformational change of CD8 binding loop, whereas minimum structure change by the substitution at residue 228 is expected. It is therefore speculated that minimum structure change of CD8 binding loop by substitution at residue 228 may influence binding affinity of CD8, which abrogates recognition of CD8-dependent CTL but not IL-2 production of the CD8-dependent T cell hybridoma.

Amino Acid Sequence↗
PubMed1993

[A case of familial insulin resistance due to type A insulin receptor disorder].

We report a case of familial insulin resistance due to Type A insulin receptor disorder. The patient, a product of consanguineous marriage, was a 34-year-old man who had had diabetes mellitus since the age of 14 years. He was treated by insulin therapy but became blind due to diabetic retinopathy at the age of 25 years. He was 154 cm tall and weighed 41kg. He had hirsutism and acanthosis nigricans. Laboratory data revealed hyperinsulinemia (140-350 microU/ml), and glucose clamp study showed insulin resistance, i.e. decreased glucose metabolic clearance rate, 20% of normal. Insulin binding was decreased to 10.7-16.6% of normal in erythrocytes, cultured fibroblasts and transformed lymphocytes. Glucagon stimulated C-peptide levels decreased gradually during a 3 year follow-up period. Homologous missense mutation from Proline193 to Leucine193 was found in this patient. Heterologous mutation was found in his mother who showed mild diabetes but did not show hirsutism or acanthosis nigricans. These findings suggested that the patient's father had this mutation in his insulin receptor gene and that the homologous mutation gene provoked more severe diabetes mellitus than heterologous mutation in this case. The efficacy of sulfonylurea agents was seen in this patient. Furthermore, sulfonyl urea agents may be indicated for treating these patients, probably by increasing insulin sensitivity.

Acanthosis Nigricans↗
PubMed1993

Two novel types of human papillomavirus, HPV 63 and HPV 65: comparisons of their clinical and histological features and DNA sequences to other HPV types.

An association exists between verrucae presenting with specific histological features and the type of HPV inducing the lesion. An HPV 1 induced lesion is associated with a granular type of intracytoplasmic inclusion body (Gr-ICB), whereas HPV 4 is associated with the homogeneous type of ICB (Hg-ICB). A third type of inclusion body, a filamentous type (F1-ICB), was found to be present in multiple punctate keratotic lesions. A novel type of papillomavirus, HPV 63, was present in such lesions. After cloning, characterization and sequencing of its DNA genome, HPV 63, although still very distinct (< 66% nucleotide homology), could be grouped with HPV 1. Upon histological examination of verrucous lesions presenting clinically with grey to black pigmentation, the Hg-ICB present were very characteristic. These lesions were infected with HPV 4, HPV 60, or HPV 65. The majority of the lesions contained the novel type HPV 65. This viral DNA was isolated and characterized. Its DNA sequence has an 83% homology to that of HPV 4, whereas both are more distantly related to HPV 60, an HPV isolated from an epidermoid cyst.

Base Sequence↗
PubMed1993

A mutation (Trp1193-->Leu1193) in the tyrosine kinase domain of the insulin receptor associated with type A syndrome of insulin resistance.

We evaluated a 35-year-old diabetic male patient with type A insulin resistance, showing acanthosis nigricans. Insulin binding to the patient's Epstein-Barr-virus transformed lymphocytes was mildly reduced. The maximal insulin-stimulated autophosphorylation of the insulin receptor from the patient's transformed lymphocytes was decreased to 45% of that from the control subjects. On examination, the biological activities of insulin and insulin-like growth factor I in the patient's cultured fibroblasts, insulin sensitivity of amino isobutyric acid uptake and thymidine incorporation was decreased, but insulin-like growth factor I action was normal. The sequence analysis of amplified genomic DNA revealed that the patient was heterozygous for a mutation substituting Leu for Trp at codon 1193 in exon 20 of the insulin receptor gene. The patient's mother and sister were also heterozygous for a mutation in the insulin receptor gene that substituted Leu for Trp1193 in the beta subunit of the receptor. Therefore, the mutation causes insulin resistance in a dominant fashion. They were less hyperglycaemic and more hyperinsulinaemic than the proband after glucose loading. The mother had diabetes mellitus but did not show acanthosis nigricans, while the sister did not have diabetes and showed acanthosis nigricans. These results suggest that this mutation causes defective tyrosine kinase activity of the insulin receptor, which results in insulin resistance. Insulin action and phenotypic appearance may be mediated by different factors.

Adult↗
PubMed1993

Recognition of the Qa-2k tumor antigen by T cell receptor gamma/delta of an immunopotentiator-induced tumoricidal T cell of mice.

Tumor-specific expression of Qa-2k antigen coded by the Q5k gene on various mouse tumor cells and immunological response of the host mice to the antigen have been demonstrated [Seo et al. (1992) J Exp Med 175: 547; Tanino et al. (1992) Cancer Immunol Immunother 35: 230]. The possibility was examined that Qa-2 antigen is one of the recognition target molecules of immunopotentiator-induced, H-2-nonrestricted tumoricidal lymphocytes of Qa-2-mice. Lymphocytes stimulated in vivo with P. acnes or culture-induced anomalous killers of B6.K1 mice did not exhibit significant in vitro cytotoxicity against B6.K1 lymphoblasts but lysed their Qa-2,3-congenic counterpart B6 lymphoblasts. To demonstrate the Qa-2 specificity of such cytotoxic cells more precisely, an L cell transformant clone (LQ7b/Kb), which expressed the alpha 1 and alpha 2 domains of the Qa-2 antigen (Q7b gene product), was generated by transfecting a cloned plasmid DNA containing a hybrid gene constructed from the 5' half of the Q7b gene and the 3' half of the H-2Kb gene (pQ7b/Kb). Using LQ7b/Kb cells as the target cells and the nylon-wool-nonadherent fraction of lymphocytes from P. acnes-stimulated (C3H/He x B6.K1)F1 mice (H-2k, Qa-2-) as the effector cells of the in vitro cytotoxicity reaction, the presence of cytotoxic cells that recognize the alpha 1/alpha 2 region of the Q7b gene product was demonstrated. The cytotoxic activity was dependent on T cells bearing T cell receptors of the gamma/delta type (TCR gamma/delta). The (C3H/He x B6.K1)F1 effector cells, as well as the B6.K1 effector cells also lysed BW5147 lymphoma cells (Qa-2k+) derived from AKR mice (Qa-2-, H-2k). By target-competition experiments it was shown that some of the effector cells lytic to BW5147 were identical to those that lysed LQ7b/Kb. Therefore some of the tumoricidal cells induced by the immunopotentiator interact with the target tumor cells through recognition of the alpha 1/alpha 2 region of the Qa-2k tumor antigen by TCR gamma/delta.

Adjuvants, Immunologic↗
PubMed1993

cDNA sequence diversity and genomic clusters of major surface glycoprotein genes of Pneumocystis carinii.

The major surface glycoprotein (MSG) of Pneumocystis carinii plays a crucial role in the pathobiology of P. carinii, which often causes fatal pneumonia in AIDS patients. The cDNAs encoding MSG antigens were cloned from a lambda gt11 expression library of rat-derived P. carinii by immunoscreening. The cloned cDNAs constituted a gene family containing approximately 70% amino acid identity between subtypes. The diversity of MSG cDNAs was high and reflected the genomic structure of MSG genes clustered in the P. carinii chromosomes. These multiple genes may account for the high-level expression of MSG that could generate potential variations in the cell surface. Moreover, the MSG sequences have significant sequence homology to tropomyosins and myosins, suggesting physical or functional association with the membrane cytoskeleton.

Amino Acid Sequence↗
PubMed1993

Varied clinical morphology of HPV-1-induced warts, depending on anatomical factors.

The clinical and histological features of 49 lesions induced by human papillomavirus type 1 (HPV-1) were studied. The majority of cases showed the typical clinical features and location of such lesions. They were usually located on the ventral or lateral surfaces of the hands or feet, and were dome-shaped lesions with a central depression. However, HPV-1-induced lesions located on other body areas displayed different clinical features, such as those of common warts, a digitate wart, and a cutaneous horn. One lesion on a healing burn scar had a herpes-like appearance. As these 49 lesions were induced by the same type of HPV (HPV-1), differences in their clinical features are likely to have been due to host-related factors.

Adolescent↗
PubMed1993

Ala1048-->Asp mutation in the kinase domain of insulin receptor causes defective kinase activity and insulin resistance.

We identified a heterozygous missense mutation that substituted aspartic acid (GAC) for alanine (GCC) at codon 1048 of the insulin receptor gene in a patient who displayed typical symptoms of Type A syndrome of insulin resistance. The proband's mother and younger brother were also found to be heterozygous for the mutation. We constructed the identified mutant insulin receptor cDNA by site-directed mutagenesis, transfected the mutant cDNA into COS 7 cells, and found that kinase activity of the mutant insulin receptors was markedly impaired. Ala1048 is located in the kinase domain of the insulin receptor beta-subunit and is conserved in most of protein-tyrosine kinases. Besides, neighboring Glu1047 is invariant in all protein kinases and is thought to be involved in interaction with ATP. Photoaffinity labeling of the mutant insulin receptor with ATP analogue, 8-azido (alpha-32P)ATP was not influenced by the mutation, suggesting that the mutation did not inhibit ATP binding but possibly interfered with subsequent phosphoryl transfer. Insulin-stimulated phosphorylation of exogenous substrate by partially purified insulin receptors prepared from COS 7 cells that were cotransfected with wild-type and mutant insulin receptor cDNAs was markedly impaired, whereas autophosphorylation was decreased by approximately 50% of wild-type receptors. These results indicated that the identified heterozygous substitution of Asp for Ala1048 in insulin receptor was responsible for insulin resistance of this patient.

Adolescent↗
PubMed1993

Double infection with human papillomavirus 1 and human papillomavirus 63 in single cells of a lesion displaying only an human papillomavirus 63-induced cytopathogenic effect.

BACKGROUND: Specific histologic features are associated with the presence of certain human papillomaviruses (HPV) in verrucous lesions of the skin. HPV 1 is known to be associated with eosinophilic keratohyalin-like intracytoplasmic inclusion bodies, granular in appearance, whereas the recently described HPV 63 seems to induce inclusion bodies displaying a filamentous structure. Although an infection by two distinct HPV types within a single cell has not been previously reported, we have recently treated a plantar punctate keratotic wart in which only the histologic features seen in an HPV 63-induced lesion were seen, in spite of the detection of double infection of both HPV 1 and HPV 63 DNAs, thus posing the question as to the role of the HPV 1 present in the lesion. EXPERIMENTAL DESIGN: To localize the genomes of these two viruses within the lesion, double fluorescence in situ hybridization was performed using biotin-labeled HPV 63 DNA and digoxigenin-labeled HPV 1 DNA. The distribution of the genomes of these two viruses was examined in comparison with the histologic features in the lesion. The copy numbers of HPV 63 and HPV 1 were compared on agarose gel electrophoresis, stained with ethidium-bromide. RESULTS: We demonstrated the presence of the DNA of both HPV 1 and HPV 63 within the same nucleus of a plantar wart. In spite of the double infection of these two viruses in a cell and more or less equal copy numbers of the viruses, the cytopathogenic effect of only HPV 63 was seen in the cells. CONCLUSIONS: This is the first report of double infection of two different types of HPV within the same nucleus. Our findings suggest the possible interference that two HPV types could have on each other in inducing the HPV type specific cytopathogenic effects.

Blotting, Southern↗
PubMed1992

Expression of the Qa-2k phenotype encoded by the Q5k gene on the surface of tumor cells derived from H-2k mice.

Immunological and biochemical characteristics of the Qa-2 murine nonclassical histocompatibility class 1 antigen expressed on tumor cells derived from H-2k (Qa-2-) mice were studied. It was found that the Qa-2 antigen on normal H-2b lymphocytes reacted with Qa-2-specific monoclonal antibodies (mAbs) 34-1.2, 59 (both specific to the alpha 1/alpha 2 region) and 141-15.8 (specific to the alpha 3 domain), and the Qa-2 antigen on H-2k tumor cells (Qa-2k antigen) reacted with mAbs 59 and 141-15.8, but not with 34-1.2. The normal Qa-2 antigen was susceptible to treatment with phosphatidylinositol-specific phospholipase C, but the Qa-2k antigen was insensitive to it. By Northern hybridization, polymerase chain reaction (PCR) studies on cDNA, Southern hybridization, Western blotting, and nucleotide sequence analysis, the Q5k gene was identified as the gene encoding the Qa-2k antigen expressed on BW5147 lymphoma cells derived from a mouse of AKR strain (H-2k, Qa-2-). The nucleotide sequence of PCR-amplified BW5147 Q5k cDNA showed complete agreement with the reported sequence of exons 1-5 of the Q5k gene of C3H/He. It also showed complete deletion of the region corresponding to exons 6 and 7, and a very short coding region in exon 8, resulting in very short cytoplasmic domain of the product compared with regular class 1 antigens. These characteristics were expected from the reported Q5k genomic sequence. These results revealed that the Qa-2k antigen was distinct from the normal Qa-2 antigen expressed on H-2b lymphocytes although it cross-reacted with some Qa-2-specific mAbs.

Amino Acid Sequence↗
PubMed1992

Detection of allogeneic Qa/TL and Ly specificities on murine tumor cells with IgD in tumor-regressor serum.

Serum from C3H/He mice, which show regression of MM2 tumor cells after transplantation and removal (regressor serum, RS) contains non-gammaglobulin components that cross-react with various tumor cells of mice [22, 23]. In addition to tumor cells, various allogeneic lymphocytes are also susceptible to an RS-dependent lymphocyte-mediated cytotoxic reaction. To identify tumor cell surface antigens that cause the cross-reactive host response, the serum components were analyzed by absorption of RS with allogeneic lymphocytes. RS components were found to recognize allogeneic lymphocyte antigens including Qa-2 and Ly6.2. Specificity for the Qa-2 antigen was further tested using Qa-2-congenic mice. The expression of Qa-2 antigen was detected on the surfaces of MM2 and other tumor cells derived from H-2k mice (seven among nine cell lines tested) by a membrane immunofluorescence method using a Qa-2-specific mAb. Physical characteristics of the Qa-2-specific component in RS were determined and found to differ from those of regular IgGs but to be similar to those of IgDs. Using an enzyme-linked immunosorbent assay with an IgD-specific mAb and Qa-2-lacZ fusion protein, the existence of IgD in RS with specificity for Qa-2 was confirmed. These results suggest that the RS component with Qa-2 specificity is an IgD, the specificity and physiological role of which are unknown.

Animals↗
PubMed1992

Anatomical study of the valves of the superficial veins of the forearm.

The valves of the cephalic, basilic and median cubital veins were investigated in the superficial veins of the left forearm in 9 cadavers, aged 25-95. The radial forearm flaps involving these veins are of special clinicoanatomical importance. The following results were obtained: (1) Valves were most frequently evident at Site G of the cephalic vein. No valves were present in Section A-B, (2) type B valves were located at confluences, junctions and branches and were more frequent (54.7%) than Type A (45.3%) located in the straight trunks of superficial forearm veins, (3) Type 2 valves accounted for most (82.3%), and these were followed by Type 1 and Type 4b (5.9%), Type 4a (4.4%) and Type 3 (1.5%).

Adult↗
PubMed1992

Isolation of human minor histocompatibility peptides.

Incompatibility of human minor histocompatibility (hmH) antigens induces rejection of grafts in organ transplantation and graft versus host disease in bone marrow transplantation if donor and recipient are matched for human leukocyte antigen (HLA) genes. These antigens are recognized only by T cells. We describe here the isolation of hmH peptides recognized by a hmH antigen specific, HLA-B35 restricted CTL clone which was derived from a patient who rejected the kidneys from two HLA-identical sisters. Naturally occurring hmH peptides were isolated from a donor derived B cell line and an HLA-B35 transfected human B cell line by acid elution. Analysis of various HLA class I transfectant cells demonstrated that MHC class I molecules themselves determine the peptides which are naturally processed and presented to T cells.

B-Lymphocytes↗
PubMed1992

Expression of CA 50 in normal human skin: comparative study of CEA and CA 19-9.

Normal skin specimens from different body sites were estimated for the expression of CA 50 in comparison with CA 19-9 and CEA. Expression of CA 50 and CA 19-9 was observed in the ductal system and a small part of the secretory portion of eccrine units, but never in any other skin components including apocrine units. CEA was expressed on the ductal and a small part of the secretory portion of apocrine units as well as on those of eccrine units. However, the expression pattern and intensity in eccrine units were different from those of CA 50 or CA 19-9. We concluded that CA 50 was strongly expressed in the normal ductal system of eccrine units and hence could be standardized to stain the eccrine ductal portion and that immunohistochemical comparative studies with CA 19-9 or CEA might be a good methodological technique for discriminating an eccrine or apocrine origin for some skin disorders.

Antigens, Tumor-Associated, Carbohydrate↗