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Biomedical subjects

Y Kitagawa

Publications and source records attributed to Y Kitagawa.

At least 199 records · Page 11Linked to original sources
PubMed1995

Additional crystal forms of the E. coli class II fructose-1,6-bisphosphate aldolase.

We have obtained two additional crystal forms of the metal-dependent class II fructose-1,6-bisphosphate aldolase from Escherichia coli. Crystals in the shape of elongated plates have unit-cell dimensions a = 73.4, b = 120.0, c = 190.1 A, orthorhombic space group P2(1)2(1)2(1). Monoclinic prisms have unit-cell dimensions a = 67.7, b = 104.3, c = 52.8 A, beta = 105 degrees, space group P2(1). Diffraction to slightly better than 3.0 A, has been observed for both forms using in-house and synchrotron facilities. These crystal forms may aid the structure solution of this enzyme by presenting additional forms for heavy-atom derivatization. These forms have multiple copies of the enzyme in the asymmetric unit and averaging methods might also be useful in the analysis.

Journal Article↗
PubMed1995

Deciduous dental morphology of the prehistoric Jomon people of Japan: comparison of nonmetric characters.

Morphological variations of the deciduous dentition are as useful as those of the permanent dentition for determining the biological affinities of human populations. This paper provides material on morphological variations of deciduous teeth of the prehistoric Japanese population from the Late and the Latest Jomon Period (ca. 2000-ca. 300 B.C.). The expression of nonmetric traits of the deciduous teeth in the Jomon sample shows a closer affinity with modern Japanese and Native American samples than with American White, Asiatic Indian, and African samples. However, the frequency of shoveling in deciduous upper incisors in the Jomon sample is lower than those in modern Japanese and Native American samples. The Jomon sample also expresses a much higher frequency of cusp 6 in deciduous lower second molars than seen in modern Japanese, Ainu, and Native American samples. The frequency in the Jomon sample is equal to that in the Australian Aboriginal sample, which shows cusp 6 most frequently among the samples compared. A somewhat low incidence of incisor shoveling in the Jomon sample was also reported in the permanent dentition (Turner [1976] Science 193:911-913, [1979] Am. J. Phys. Anthropol. 51:619-635, [1987] Am. J. Phys. Anthropol. 73:305-321, [1990] Am. J. Phys. Anthropol. 82:295-317; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182, 88:183-196). However, the frequency of cusp 6 in the Jomon sample shows no significant difference from those of Northeast Asian or Native American samples in the permanent dentition (Turner [1987] Am. J. Phys. Anthropol. 73:305-321; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182, 88:183-196). Evidently, some nonmetric traits express an inter-group difference only in the deciduous dentition.

Africa, Southern↗
PubMed1995

Induction of anti-Purkinje cell antibodies in vivo by immunizing with a recombinant 52-kDa paraneoplastic cerebellar degeneration-associated protein.

We immunized five different strains of mice with the recombinant human PCD17 protein, which is recognized by anti-Purkinje cell antibodies in the sera of patients with paraneoplastic cerebellar degeneration, and explored whether or not antibodies against cerebellar Purkinje cells could be induced in vivo. Autoantibodies against the cytoplasmic protein of Purkinje cells and other neurons were raised in all the strains of mice. These antisera stained the cytoplasm of cytoplasm of the Purkinje cell in a coarse, granular pattern, but spared the nucleus. The antisera did not stain cerebellar granular cells. This pattern of immunostaining seen with the mouse antisera is similar to that seen with the human PCD sera, but more widespread cells in the central nervous system were stained with these antisera. The titers of the induced antibodies were comparable to or even higher than those of humans. The deposition of IgG was also demonstrated in the cytoplasm of Purkinje cells in the immunized mice. In spite of the generation of anti-Purkinje cell antibodies in vivo, neither clinical nor pathological changes consistent with cerebellar degeneration were detected 1 year following the first immunization.

Animals↗
PubMed1995

Effect of endogenous and exogenous EGF on the growth of EGF receptor-hyperproducing human squamous cell carcinoma implanted in nude mice.

The effect of epidermal growth factor (EGF) on the biological behaviour of human tumours in vivo is still controversial. We investigated the effect of EGF on the growth of an EGF receptor-hyperproducing human epidermoid carcinoma, A431 tumour, and on a human small-cell lung carcinoma, H69 tumour, without detectable EGF receptor by using sialoadenectomised (sialex) mice as an endogenous EGF-suppressed animal model. The plasma EGF concentration in the sialex athymic mice was significantly lower than that in the sham-operated mice (P < 0.05). After exogenous EGF replacement with an implanted minipump, the plasma EGF concentration was significantly increased in both groups (P < 0.05). There was no significant difference between the body weight growth curves of sialex and sham-operated mice with and without EGF treatment. The tumour weight of A431, both estimated and measured in sialex mice, was significantly lower than that in sham-operated control mice (P < 0.05), and the growth of A431 tumour was significantly increased by exogenous EGF treatment (P < 0.05). Mitotic activity of these tumours detected by immunohistochemical staining for incorporated bromodeoxyuridine indicated a mitosis-stimulatory effect of endogenous and exogenous EGF on A431 tumours. In contrast to these findings on A431 tumours, a growth-stimulatory effect of endogenous and exogenous EGF was not observed in the H69 tumour. These results suggest a growth-promoting effect of physiological levels of endogenous EGF on EGF receptor-hyperproducing human tumours in vivo.

Animals↗
PubMed1995

Determination of beta-adrenoceptor subtype on rat isolated ventricular myocytes by use of highly selective beta-antagonists.

1. The relative proportions of beta 1- and beta 2-adrenoceptors were determined by radioligand binding studies in three different rat myocardial preparations: membranes prepared from rat ventricle (ventricular membranes), membranes prepared from rat isolated ventricular myocytes (myocyte membranes), and myocytes isolated from rat ventricle (myocytes). 2. Competition experiments using CGP 20712A or ICI 118,551 with [125I]-iodocyanopindolol ([125I]-ICYP) revealed high- and low-affinity binding sites in ventricular membranes. The concentration at which each beta-antagonist occupied 100% of its high-affinity binding sites was 300 nM for CGP 20712A (beta 1-adrenoceptor) and 50 nM for ICI 118,551 (beta 2-adrenoceptor). 3. The density of high-affinity (beta 1-adrenoceptor) and low-affinity (beta 2-adrenoceptor) binding sites for CGP 20712A was measured by a saturation experiment using [125I]-ICYP in the presence and absence of 300 nM CGP 20712A. In ventricular membranes, the proportions of high-affinity and low-affinity binding sites for CGP 20712A were 73% and 27%, respectively, whereas in myocyte membranes, the corresponding figures were 90% and 10%, respectively. The density of low-affinity binding sites for CGP 20712A in ventricular membranes, defined as [125I]-ICYP-specific binding in the presence of 300 nM CGP 20712A, was decreased by addition of 50 nM ICI 118,551, whereas that in myocyte membranes was not affected. 4. In myocytes, specific binding of [125I]-ICYP and [3H]-CGP 12177 was not detected by saturation experiments performed in the presence of 300 nM CGP 20712A. 5 In myocytes, the activation of adenylate cyclase caused by beta2-adrenoceptors was not detected in the presence of 10 nM, 100 nM or 1000 nM CGP 20712A, which selectively antagonized beta1-adrenoceptors.Furthermore, the concentration-response curve for isoprenaline-stimulated cyclic AMP accumulation was not shifted by 10 nm or 100 nM ICI 118,551, which selectively antagonized beta2-adrenoceptors, but was shifted to the right by 1000 nM ICI 118,551.6 These results indicate that beta2-adrenoceptors are not present on rat ventricular myocytes and that beta2-adrenoceptor stimulation does not cause any detectable production of cyclic AMP. We conclude that only beta1-adrenoceptors exist on rat ventricular myocytes.

Adrenergic beta-Agonists↗
PubMed1995

[Restenosis after percutaneous transluminal coronary angioplasty in the elderly--risk factor analysis].

Utilization of percutaneous transluminal coronary angioplasty (PTCA) has dramatically expanded even in the management of elderly patients with coronary artery disease. However, restenosis after successful PTCA remains the major problem limiting the long-term efficacy of the procedure. Reported restenosis rates vary from 25 to 43%. In order to determine the relationship of restenosis to coronary risk factors in the elderly, we analyzed the data in 87 patients who had undergone PTCA and angiography before and 3 to 6 months after PTCA. Of these, 29 patients were 65 years of age or older (elderly group) and 58 were less than 65 years of age (younger group). Restenosis, defined as a luminal narrowing of greater than 50% at follow-up time, was found in 20 of the elderly group (69.0%), and in 26 (44.8%) of younger group (p < 0.0001). Total cholesterol, LDL cholesterol, apolipoprotein B (apo B), and the ratio of apoB/apoA1 in the elderly group were significantly lower than those in the younger group. HDL cholesterol levels were lower than 40 mg/dl in both groups (not significant). Each group was subdivided into two types; restenosis type and non-restenosis type. There were no significant differences in serum lipid, apolipoprotein, and lipoprotein(a) levels between the 2 subtypes in each group. The degree of coronary atherosclerosis calculated by Gensini's method, the number of damaged coronary vessels, diabetes mellitus, hypertension, and smoking did not appear to affect the rate of restenosis in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

[A case of Guillain-Barré syndrome associated with anti-GM2 antibody due to cytomegalovirus infection--special reference to the effect of ganciclovir].

We report a case of Guillain-Barré syndrome (GBS) associated with anti-GM2 antibody caused by cytomegalovirus (CMV) infection. A 27-year-old man was admitted to our hospital because of muscle weakness in all his extremities. He had no background of immunological abnormalities. Within 5 days, generalized muscular weakness had progressed so rapidly that he suffered respiratory dysfunction and dysphagia. Throughout the entire clinical course, enzyme immunoassay (serum) and enzyme-linked immunosorbent assay (CSF) for CMV were carried out serially. Only antibodies against CMV were elevated during the clinical course in the serum and CSF. These findings supported the idea that he had developed GBS due to isolated CMV infection. We examined the reactivity of GBS sera with crude ganglioside fraction, and only anti-GM2 antibody was recognized on a high-performance thin-layer chromatogram plate in this case. Although the anti-GM2 antibody was decreased transiently by plasmapheresis, the clinical symptoms progressed. The symptoms advanced very rapidly during high-dose gammaglobulin therapy associated with reelevation of the anti-GM2 antibody. Following ganciclovir administration, however, the symptoms became diminished within 7 days and the anti-GM2 antibody fell dramatically. We speculate that the reason for the observed effectiveness of ganciclovir was direct suppression of activation of CMV, followed by the inhibition of the production of demyelinating antibodies including the anti-GM2 antibody.

Adult↗
PubMed1995

alpha-Tocopherol enhances the hypocholesterolemic action of sesamin in rats.

The effect of alpha-tocopherol on the hypocholesterolemic action of sesamin was examined in rats given a cholesterol-enriched diet. When different levels (0.05 and 0.2%) of sesamin were fed, the supplementation of 1% alpha-tocopherol significantly accentuated the hypocholesterolemic action of sesamin, particularly with the higher sesamin level, although alpha-tocopherol alone did not affect the concentration of serum cholesterol. The dose-dependent promoting effect of alpha-tocopherol on the hypocholesterolemic action of sesamin was confirmed by supplementing different levels (0.2 and 1%) of alpha-tocopherol to a fixed level of sesamin (0.2%). alpha-Tocopherol was still effective at the 0.2% level. The metabolism of sesamin in the liver S9 fraction appeared to be interfered with alpha-tocopherol in vitro, suggesting a possible role of alpha-tocopherol in maintenance of the availability of sesamin.

Animals↗
PubMed1994

Expression and binding activity of the carboxyl-terminal portion of the core protein of PG-M, a large chondroitin sulfate proteoglycan.

PG-M is a large chondroitin sulfate proteoglycan that has been shown to be expressed in the prechondrogenic condensation area of the developing chick limb buds. We previously isolated cDNA clones encoding the core protein of PG-M (Shinomura, T., Nishida, Y., Ito, K., and Kimata, K. (1993) J. Biol. Chem. 268, 14461-14469). The amino acid sequence deduced from the cDNA analysis revealed the presence of two epidermal growth factor-like domains, a C-type lectin-like domain, and a complement regulatory protein (CRP)-like domain at the COOH terminus. The COOH-terminal portion has been expressed as a fusion protein with glutathione S-transferase in Escherichia coli to test its carbohydrate binding activity using affinity chromatography. The purified fusion protein binds to immobilized D-mannose, D-galactose, L-fucose, and N-acetyl-D-glucosamine in a calcium-dependent manner. Furthermore, the fusion protein binds to heparin- or heparan sulfate-Sepharose. To investigate roles of each COOH-terminal domain, we have made a truncated construct which lacks the CRP-like domain and determined if the CRP-like domain is involved in the binding activity. The removal of this domain resulted in the complete loss of both C-type lectin-like and heparin binding activities. The results suggest that a whole set of epidermal growth factor-, lectin-, and CRP-like domains may serve a functional structure for these bindings.

Aggrecans↗
PubMed1994

Structural characteristics for biological activity of heat-stable enterotoxin produced by enterotoxigenic Escherichia coli: X-ray crystallography of weakly toxic and nontoxic analogs.

Heat-stable enterotoxin (ST) produced by a pathogenic strain of Escherichia coli exerts its function by binding to a membrane-bound guanylyl cyclase on intestinal epithelial cell membranes, which in turn catalyzes the production of cyclic GMP as a second messenger in the cells. To elucidate the structural requirements for the biological activities of ST, we synthesized [Mpr5,Gly13]STp(5-17) and [Mpr5,Leu13]STp(5-17), which are weakly toxic and nontoxic analogs of STp, in which the toxic domain consists of the sequence from Cys at position 5 to Cys at position 17. In these analogs, Cys at position 5 is replaced by Mpr (beta-mercaptopropionic acid) and Ala at position 13 by Gly and Leu, respectively. We examined these analogs by X-ray diffraction analysis using direct methods and refined the structures to crystallographic R factors of 7.3% and 6.6% using 5492 and 5122 data, respectively, observed > 3 sigma (Fo) with a resolution of 0.89 A. These peptides have a right-handed spiral structure consisting of three structural segments: an N-terminal 3(10) helix, a central type I beta-turn, and a C-terminal type II beta-turn. These structures show minor differences from that of [Mpr5]STp(5-17), the fully toxic analog of heat-stable enterotoxin [Ozaki et al. (1991) J. Biol. Chem. 266, 5934-5941], suggesting that the decrease and loss of the biological activities of [Mpr5,Gly13]STp(5-17) and [Mpr5,Leu13]STp(5-17), respectively, are not caused by structural changes but are associated with the direct interaction of Ala13 with the receptor protein. Careful comparison of these structures in crystalline states revealed that ST has the following structural characteristics: (i) inherent flexibility at the junctions of the three segments and in the central segment, which includes the putative receptor-binding residues, Ala13, (ii) a specific hydrophobic character around the central segment, and (iii) an unexpected C-terminal folding similar to those of functionally unrelated peptides that are known to be ionophores.

Amino Acid Sequence↗
PubMed1994

A hippocampal protein associated with paraneoplastic neurologic syndrome and small cell lung carcinoma.

A hippocampal 38 kd autoantigen recognized by an autoantibody from the serum of a patient with paraneoplastic limbic encephalitis (PLE) and small cell lung carcinoma (SCLC) was isolated by screening a human hippocampal cDNA library. The 1,991-nucleotide ple21 clone was obtained and the deduced 350-residue protein encoded by the ple21 cDNA clone was found to be highly homologous to the neuron-specific RNA recognition motifs (RRMs)-containing proteins. The homologies were confined to the RRMs and the RRM connecting region. The presence of RRM in the antigenic protein may be important in the pathogenesis of SCLC-associated paraneoplastic neurologic syndrome.

Amino Acid Sequence↗
PubMed1994

Prognostic factors of renal dysfunction induced by environmental cadmium pollution.

To assess the influence of environmental cadmium (Cd) exposure on long-term outcome, a follow-up study was conducted from 1981-1982 to March 1991 on 3178 inhabitants living in the Cd-polluted Kakehashi River basin. The standardized mortality ratios of the urinary beta 2-microglobulin (beta 2-MG)-, protein-, and amino acid-positive subjects of both sexes and the urinary glucose-positive female subjects were higher than those of the subjects with urinary-negative findings or the general Japanese population during the observation period. After adjusting for age using Cox's proportional hazards model, significant associations were found between mortality and urinary indices. In multiple comparisons using all of the indices, urinary protein and beta 2-MG in the women and urinary protein in the men were the factors most contributing to the mortality rates. In the urinary protein-negative female group as well, a significant association was found between urinary beta 2-MG and mortality. These results suggest that the prognosis of subjects with Cd-induced renal dysfunction is unfavorable, with the mortality rate increasing even in the early stage of proximal tubular dysfunction. Urinary protein and urinary beta 2-MG are important prognostic factors, with the latter, in particular, considered to be useful as an early index predictive of premature mortality.

Amino Acids↗
PubMed1994

Two collagen-binding proteins, osteonectin and HSP47, are coordinately induced in transformed keratinocytes by heat and other stresses.

pSE48 was one of six clones selected by differential colony hybridization as a cDNA coding for mRNA expressed in parietal endoderm-like F9 cells and not in primitive endoderm-like F9 cells. It was sequenced and identified as a segment of mouse osteonectin (SPARC) cDNA. We found osteonectin to be heat-inducible in some cells. Expression and secretion of osteonectin were then investigated using mouse (Pam 212) and human (HSC-1) keratinocyte cell lines. Both the mRNA levels and the secretion of osteonectin increased concurrently when Pam and HSC-1 cells cultured in low calcium medium were exposed to various stresses including heat shock and treatment with sodium arsenite or L-azetidine-2-carboxylic acid. Another collagen-binding stress protein, HSP47, was also found to be expressed, synthesized, and stress-inducible in the keratinocyte cell line. The degree of HSP47 induction by various stresses was not so prominent as that of HSP70 but greater than that of osteonectin. The time courses of osteonectin and HSP47 induction by heat shock were similar to each other and distinct from HSP70; they were slower and more persistent than HSP70. We identified a heat shock element-like sequence in the promoter region of the mouse and bovine osteonectin genes. This sequence might participate in the stress induction of osteonectin. Thus, osteonectin and HSP47 share another common feature, stress-inducibility, as well as collagen-binding capacity and inducibility through differentiation, although they are quite distinct in their amino acid sequence and distribution.

Animals↗
PubMed1994

N-glycosylation of erythropoietin is critical for apical secretion by Madin-Darby canine kidney cells.

Erythropoietin (Epo) has three N-linked carbohydrate chains at positions 24, 38, and 83 in its 166-amino acid residues. When the human wild-type Epo was expressed in the polarized Madin-Darby canine kidney (MDCK) epithelial cells, Epo was preferentially secreted from the apical domain. The polarized secretion was perturbed by the treatment of the cells with tunicamycin, suggesting the involvement of N-linked carbohydrate chains in the apical sorting mechanism in MDCK cells. Replacement of asparagine residues at all N-glycosylation sites of Epo with glutamine by site-directed mutagenesis resulted in roughly equal secretion from apical and basolateral domains. Comparative studies on MDCK clones expressing the mutant Epos lacking one or two of the three N-glycosylation sites in every possible combination showed that the N-linked carbohydrate chain at position 38 is critical for the polarized secretion. Nocodazole, a microtubule-disrupting drug, reversed the polarized secretion of the wild-type Epo from the apical to basolateral preference with little change in the total secretion. Hepatocyte growth factor, a scatter factor known to induce the tubule-like structure of MDCK cells, caused almost equal secretion of the wild-type Epo into the apical and basolateral sides, although the tight junctions of MDCK cells remained intact.

Animals↗
PubMed1994

Induction of chilling resistance by water stress, and cDNA sequence analysis and expression of water stress-regulated genes in rice.

Exposure of seedlings of a chilling-sensitive variety of rice (Oryza sativa L. cv. Wasetoittu) to water stress (0.5 M mannitol, 30 min) at room temperature induced a degree of chilling resistance. No such resistance was induced by exogenous abscisic acid (ABA) application (10 microM, 60 min). Upon short-term water stress, new transcripts were expressed in both seedlings and suspension-cultured cells. We suggest that the genes induced by short-term water stress, and not those induced by ABA, are related to acquired chilling resistance in this chilling-sensitive rice variety. A total of nine different cDNA clones, specifically induced by short-term water stress, were isolated by differential hybridization and partial sequencing. Northern hybridization analysis using RNAs from the seedlings subjected to chilling after water stress treatment reveal three distinct groups of above mentioned nine cDNA clones: wsi (water stress-induced) 18, 76, and 724, representative of genes whose expression increases, decreases, and remains almost fixed during chilling, respectively. The nucleotide and deduced amino acid sequences of the three representative clones were determined. Characteristic features of wsi18 are the presence of one set of amino acid sequence repeats, a conserved amino acid sequence common to LEA-group genes in the N-terminal region, and an alanine- and lysine-rich tract in the C-terminal region.

Abscisic Acid↗
PubMed1994

Poststroke depression.

Sixty-eight patients with stroke were investigated to assess their mood state. Nearly half of them were found to be depressed; according to DSM-III-R, 6 of these were diagnosed as suffering from major depression and the rest from adjustment disorder with depressive mood. A significant relationship was found between mood state on the one hand, and daily living activities and Type A behavior pattern on the other.

Activities of Daily Living↗