Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 505 records · Page 28Linked to original sources

PubMed1997

Breast cancer risk factors according to combined estrogen and progesterone receptor status: a case-control analysis.

Breast cancers demonstrate a gradient of responsiveness to endocrine therapy according to hormone receptor status, with tumors positive for both estrogen and progesterone receptors responding most favorably. The authors hypothesized that reproductive risk factors, which are probably mediated by endogenous hormones, would also differ according to receptor status, and that tumors positive for both receptors would exhibit the highest risk. Information on risk factors was obtained from 1,154 breast cancer cases and 21,714 cancer-free controls at the Aichi Cancer Center Hospital, Nagoya, Japan between 1988 and 1992. Receptor status was known for 40% of cases. For a given risk factor, odds ratios with respect to the common control group for breast cancers of differing receptor status were compared using multiple polytomous logistic regression. Risk factors did not differ significantly according to estrogen receptor status. However, age at diagnosis/interview, occupation, age at menarche, menstrual regularity at ages 20-29 years, and cigarette smoking differed significantly or borderline significantly in effect according to progesterone receptor status. Stratification of cases according to joint estrogen and progesterone receptor status indicated that estrogen receptor status did not modify this difference in effect. This study did not support the hypothesis of a gradient of risk for reproductive factors according to hormone receptor status. The authors recommend that the finding that some risk factors differ according to progesterone receptor status should be pursued in further studies.

Adult↗

PubMed1997

Synthesis and antimetastatic activity of L-iduronic acid-type 1-N-iminosugars.

L-Iduronic acid-type 1-N-iminosugars, (3R,4S,5R,6R)- and (3R,4S,5S,6R)-6-acetamido-4-amino-5-hydroxypiperidine-3-carboxylic acid (6 and 7, respectively), (3R,4S,5R,6R)-6-acetamido-4- guanidino-5-hydroxypiperidine-3-carboxylic acid (8), and (3R,4S,5R,6R)-4-amino- and -guanidino-5-hydroxy-6-(trifluoroacetamido) piperidine-3-carboxylic acid (9 and 10, respectively), were synthesized from siastatin B (1), isolated from Streptomyces culture, by the intramolecular Michael addition of O-imidate to its alpha,beta-unsaturated ester through cis oxiamination as a key step. Preincubation of B16 BL6 cells with these compounds inhibited invasion of the cells through reconstituted basement membranes. Pulmonary metastasis of B16 BL6 cells in mice was remarkably inhibited by pretreatment of the cells with these compounds in culture.

Animals↗

PubMed1997

Murine interleukin 4 transgenic heart allograft survival prolonged with down-regulation of the Th1 cytokine mRNA in grafts.

BACKGROUND: Data supporting the differential activation of T helper (Th) 2 cells in transplantation acceptance/tolerance in rodents have been presented by several investigators. However, the differential activation of Th2 cells may be simply the result of allograft acceptance/tolerance induction instead of a contribution to the maintenance of grafts. METHODS: Therefore, we established interleukin (IL)-4 transgenic mice under the control of a cardiac alpha-myosin heavy chain promotor and transplanted IL-4-expressing heart allografts into unmodified recipients to determine the actual contribution of the Th2 bias to allograft acceptance. RESULTS: Among 16 newborn C57BL/6J (B6) mice, three were positive for the IL-4 transgene. Serum IL-4 levels of transgenic versus control B6xC3H F1 mice were not statistically different. Reverse-transcriptase polymerase chain reaction showed that the transgenic B6xC3H F1 mice expressed IL-4 mRNA in the heart and in the lung, whereas control mice did not express IL-4 in any organ. IL-4 mRNA expression in the transgenic but not in the control heart was also confirmed by RNAse protection assay and fluorescence in situ hybridization. The survival of IL-4 transgenic B6xC3H heart grafts heterotopically placed in C3H recipients was prolonged compared with that of nontransgenic grafts (19.0+/-9.1 vs. 6.8+/-2.2 days, P=0.003). Interferon-gamma mRNA expression in IL-4 transgenic heart grafts on the fifth posttransplant day as assessed by Northern blotting was suppressed compared with that in control grafts. Reverse-transcriptase polymerase chain reaction analysis showed that IL-2 mRNA was suppressed in the IL-4 transgenic grafts compared with that in control grafts, while IL-4 mRNA was observed only in IL-4 transgenic grafts. IL-10 mRNA was detected at similar levels in both transgenic and control grafts. CONCLUSIONS: A Th2 bias may contribute to allograft acceptance in part by inducing the down-regulation of Th1-cytokine mRNAs, but it may not be sufficient to induce indefinite graft survival.

Animals↗

PubMed1997

Transgenic expression of a novel thymic epithelial cell antigen stimulates abberant development of thymocytes.

We previously reported a novel thymic stromal cell Ag, HS9, as a potent molecule participating in intrathymic T cell development. HS9 Ag is expressed on thymic stromal cells especially in the cortex but not on thymocytes. In the present study, we isolated and characterized a novel cDNA, N14, encoding HS9 Ag. Sequencing analysis of N14 cDNA has revealed it to be a novel one without any significant homology to previously reported functional molecules. COS7 cells transfected with expression vectors harboring N14 cDNA became reactive with HS9-specific mAb. Northern blot analysis and in situ hybridization revealed that several tissues that are positive for HS9 mAb expressed N14 mRNA. To examine the role of this molecule in T cell development, transgenic mice were generated. In situ hybridization and immunohistochemical study showed that the transgene was significantly overexpressed on both cortical and medullar thymic stromal cells but not on thymocytes. Flow cytometric analyses showed that the percentages of mature CD4- CD8+ or CD4+ CD8- thymocytes in transgenic mice were approximately twice and triple, respectively, those in control littermates. Moreover, substantial CD4+ CD8+ thymocytes appeared to have high levels of TCR compared with peripheral T cells. Histologic examination revealed that transgenic mice had thin cortex and relatively developed medulla. These data indicate the critical role of the N14 gene in T cell development.

Amino Acid Sequence↗

PubMed1997

Tyrosine hydroxylase (TH)-only-immunoreactive non-catecholaminergic neurons in the brain of wild mice or the human TH transgenic mice do not contain GTP cyclohydrolase I.

We previously reported the presence of transiently tyrosine hydroxylase (TH)-only-immunoreactive (ir), non-catecholaminergic (non-CAnergic) neurons in some brain regions of postnatal mice; anterior olfactory nucleus, medial geniculate nucleus, and spinal trigeminal nucleus, where CAnergic terminals but not cell bodies are present in the adult wild mouse. These transiently TH-ir brain regions of the postnatal wild mouse showed stable TH-immunoreactivity in the adult brain of the human TH transgenic (hTHTg) mice. TH expression was also observed in the nucleus parabigeminalis of the hTHTg mice. Using the antiserum against GTP cyclohydrolase I (GCH), first rate-limiting enzyme of the biosynthesis of tetrahydrobiopterin (BH4), the cofactor for TH, we proved that these TH-only-ir neurons in the wild mice and in the hTHTg mice were not stained with the antiserum against GCH. The results indicate that these TH-only-ir neurons which do not synthesize the BH4 cofactor do not produce dihydroxyphenylalanine, suggesting a new unknown function of TH in these neurons.

Adult↗

PubMed1997

Proprotein-processing endoprotease furin controls the growth and differentiation of gastric surface mucous cells.

Gastric surface mucous cells originate from progenitor cells at the isthmus of the gastric gland, from where the cells migrate to the luminal surface. With migration they form secretory granules and express TGF alpha. We found that proprotein-processing endoprotease furin-positive cells were layered around the upper one fourth of the gastric glands of adult rats, whereas they were distributed along an outer epithelial layer in fetal rats. Because the furin-positive cell layer was localized from the upper cell proliferating zone to the less proliferating pit-cell region in the gastric gland unit, we examined the role of furin in the growth and differentiation of surface mucous cells by using the cell line, GSM06. This cell line is derived from the gastric surface mucous cells of transgenic mice harboring the temperature-sensitive simian virus 40 T antigen. At T antigen-active temperature (33 degrees C), the cells grew to confluency, whereas at T antigen-inactive temperature (39 degrees C), the cells ceased growing. At 33 degrees C, the cells exhibited a high level of furin expression with a negligible level of periodic acid Schiff (PAS)-positive materials and a low level of TGF alpha. In contrast, at 39 degrees C the cells produced a high level of PAS-positive materials, TGF alpha, and secretory granules, with a negligible level of furin expression. To further examine the role of furin, we established a GSM06 cell line introduced with either a sense or an antisense furin cDNA. The cells with sense furin expression produced fewer PAS-positive materials and a low level of TGF alpha even at 39 degrees C, whereas the cells with antisense furin expression exhibited more PAS-positive materials and TGF alpha even at 33 degrees C. When furin expression was suppressed by its antisense oligonucleotide, the cell growth was retarded with enhanced expression of the differentiated characteristics. Thus, we conclude that furin is instrumental in controlling the growth of the surface mucous cells.

Animals↗

PubMed1997

Immunohistochemical colocalization of GTP cyclohydrolase I in the nigrostriatal system with tyrosine hydroxylase.

Immunohistochemical colocalization of GTP cyclohydrolase I (GCH) in the mouse nigrostriatal system with tyrosine hydroxylase or aromatic L-amino acid decarboxylase in the somata and terminals of GCH-positive catecholaminergic neurons are proved for the first time by a double-labeling immunofluorescence method with a confocal laser-scanning microscope. GCH-immunoreactive somata in the mouse substantia nigra have synaptic contacts with monoaminergic and non-monoaminergic terminals.

Animals↗

PubMed1997

Novel naphthalene derivatives as inhibitors of human immunoglobulin E antibody production.

A series of naphthalene derivatives with a variety of substituents at the 2-position was prepared in order to evaluate their suppressive effect on immunoglobulin E (IgE) antibody production by human peripheral blood mononuclear cells provoked with anti-CD40 antibody (alpha-CD40), interleukin-4 (IL-4), and interleukin-10 (IL-10). Compounds having a 1,4-phenylene spacer moiety tethered between the 2-naphthyl nucleus and anthranilic acid suppressed IgE antibody production in vitro in preference to that of IgG antibody without affecting cell viability. Deletion of the anthranilic acid moiety diminished the inhibitory activities. Changing the 2-naphthyl to a 1-naphthyl or phenyl nucleus led to no change in the potency, indicating that the aromatic group at this position is indispensable for the inhibitory activities. On the other hand, changing the 1,4-phenylene spacer to a 1,3-phenylene one resulted in reduced potency. Similarly, inhibitory activities were lost when the CO2H moiety at the 2-position was moved to the 3- or 4-position on the terminal benzene. These observations suggest that the conformation around the anthranilic acid moiety affects the inhibitory activities toward IgE biosynthesis. 2-(4-(2-Naphthyloxy)benzamido)benzoic acid (29) seemed to be a more potent inhibitor of IgE production than of IgG production. Insertion of a methylene between the inter-phenylene and the amide moiety resulted in 2-((4-(2-naphthyloxy)phenyl)acetamido)benzoic acid (31), which provided a stronger inhibition of both IgE and IgG production, although the selectivity toward IgE was lower than that of 29. Introduction of a benzyl group at the 6-position on the naphthalene ring considerably increased the inhibitory activity toward IgE production with an IC50 of 8.3 nM (36). The potency of 31 and 36 was retained when hydrocortisone or lipopolysaccharide was used instead of alpha-CD40 and IL-10 as costimulatory factors with IL-4, implying that these compounds may interfere with signal transduction between IL-4/IL-4 receptor cognition and genetic transcription that induce class-switching of immunoglobulin in B cells. These novel naphthalene derivatives are thus excellent candidates for further investigation with a view toward a therapeutic remedy against IgE-mediated allergic diseases.

Antibody Formation↗

PubMed1997

Co-elevation of brain natriuretic peptide and proprotein-processing endoprotease furin after myocardial infarction in rats.

We investigated the expression of the yeast Kex2 family endoproteases furin and PACE4, and brain natriuretic peptide (BNP) in the atrium and ventricle after infarction as well as the conversion of the BNP precursor gammaBNP to BNP-45. In a rat heart failure model, plasma BNP rose in two phases--first at day 3, and again at day 14. BNP mRNA, as measured by Northern blot analysis, increased strongly at day 3, then at days 14 and 28 less strongly in the atrium, and in the ventricle it increased weakly at day 3, then strongly at days 14 and 28. Furin mRNA showed the same pattern of expression as that of BNP message, whereas PACE4 message stayed unchanged after the infarction. Both furin and BNP were immunostained in the myocardium adjacent to the infarcted tissue. We suggest that after myocardial infarction, furin is co-expressed with BNP in both the atrium and ventricle, and that furin may be responsible for the conversion of gammaBNP to BNP-45.

Animals↗

PubMed1997

Heavy cigarette smokers show higher mutagenicity in urine.

We examined the mutagenicity of cigarette smoker's urine in 32 healthy male cigarette smoker and 37 healthy male non-smoker. Twenty-four-hour urine specimens were subjected to blue rayon extraction which selectively adsorb polycyclic compounds, after which the elutions were fractionated by carboxymethyl cellulose column chromatography for removing antimutagenic compounds. The mutagens were measured by using an S9-mediated Salmonella mutagenicity test on strain TA98. Compared with those with non-smokers, smokers' urine showed a significantly higher urinary level of mutagens in the acid-elutable and in the sum of all chromatography fractions. A similar tendency was also seen in the alkali-elutable fraction. The subjects were classified into three groups according to the number of smoked cigarettes. Heavy smokers, who smoked more than 20 cigarettes per day, showed a significantly higher urinary level of mutagens than both non-smokers and light smokers especially in the acid-elutable and in the sum of all chromatography fractions. Our findings suggest that smokers are exposed to a great amount of polycyclic carcinogens and mutagens by cigarette smoking. These results also suggest that urinary level of mutagens measured by using blue rayon extraction combined with carboxymethyl cellulose chromatography could be a good index for estimating the exposure to carcinogens and mutagens such as polycyclic compounds.

Adult↗

PubMed1997

Ascidian tyrosinase gene: its unique structure and expression in the developing brain.

Tadpole larvae of ascidians have two sensory pigment cells in the brain. One is the otolith cell that functions as a gravity receptor, the other pigment cell is part of a primitive photosensory structure termed the ocellus. These sensory cells, like vertebrate pigment cells, contain membrane-bounded melanin granules and are considered to reflect a crucial position in the evolutionary process of this cell type. To investigate the molecular changes accompanying the evolution of pigment cells, we have isolated from Halocynthia roretzi a gene encoding tyrosinase, a key enzyme in melanin biosynthesis. The cDNA has an open reading frame (ORF) of 596 amino acids, which is 36-39% identical in amino acid sequence to vertebrate tyrosinases. In addition, the sequence analysis of both cDNA and genomic clones reveals an unusual organization of the tyrosinase gene, an extraordinary 3' untranslated region of the transcripts with significant homology to the coding sequence, and a single short intron in the sequence encoding a cytoplasmic domain. Expression of the gene is detected first in two pigment precursor cells positioned in the neural plate of early neurulae, and later in two melanin-containing pigment cells within the brain of late tailbud embryos. Its expression pattern correlates well with the appearance of tyrosinase enzyme activity in the developing brain. These results provide the first description of pigment cell differentiation at the molecular level in the ascidian embryo, and also will contribute to a better understanding of the evolution of chordate pigment cells.

Amino Acid Sequence↗

PubMed1997

Evaluation of human conjunctival epithelium by a combination of brush cytology and flow cytometry: an approach to the quantitative technique.

Cytology using the brush technique is readily available and is a rapid means of establishing a presumptive diagnosis of ocular surface changes. However, those techniques have some limitations when obtaining cells from certain localized areas particularly if using the Cytobrush-S. We have described here a new type of brush (Accellon-M), which can collect the local cells using its spherical tip, and evaluated them by comparing with Cytobrush-S. Furthermore, we differentiated epithelial cells from nonepithelial cells that were collected by brushing, and by a combination of brush cytology and flow cytometry using an anti-keratin antibody, AE-3, which reacts with all basic epithelial keratins. Accellon-M could collect the epithelial cells from conjunctiva as effectively as with the Cytobrush-S, and there were no statistical differences between both groups. AE-3, which is reported as the marker of epithelial cells, were detected quantitatively by a combination of brush cytology and flow cytometry techniques. The result of the present study emphasizes that both the Cytobrush-S and the Accellon-M are valuable for conjunctival brush cytology. An additional positive feature of the Accellon-M may be improved cell collection from the conjunctival epithelium especially when the target cells are in a limited area. The combination of the brush cytology and the flow cytometry technique appears to be a useful adjunct as an additional diagnostic or research tool for use in the detection of various antigens in the conjunctival epithelium.

Adult↗

PubMed1997

Th2-like response and antitumor effect of anti-interleukin-4 mAb in mice bearing renal cell carcinoma.

Tumor regression in experimental systems has been linked to the activities of Th1 cells. It is, therefore, conceivable that Th2 cells interrupt the expression of tumor immunity since interleukin-4 (IL-4) and IL-10 inhibit the generation of Th1 from precursors and modulate the competence of antigen-presenting cells to activate this lymphocyte subpopulation. Naive murine renal cell carcinoma (renca) cells (1 x 10(5)) were implanted into the subcapsule of the left kidney of Balb/c and Balb/c nude mice at 6-8 weeks of age. After 14 days, Th2 cytokine (IL-4 and IL-10) mRNAs as well as transforming growth factor beta1 mRNA, assessed by reverse transcriptase/polymerase chain reaction were upregulated in the spleen of hosts upon naive renca tumor acceptance, while Th1 cytokine (IL-2 and interferon gamma) mRNAs were almost undetectable. In the renca tumor, IL-10 mRNA was detected but IL-2, interferon gamma, and IL-4 were not. Intraperitoneal administration of anti-(mouse IL-4) mAb (11B11) reduced the renca tumor size (P = 0.018) and prolonged host survival (P = 0.03), but did not reduce the acceptance rate of the tumor (P = 0.18). However, prior depletion of CD4+ or CD8+ cells with monoclonal antibodies abrogated the antitumor effects of anti-IL-4 mAb. In addition, the significant antitumor effect of anti-IL-4 mAb was not observed in Balb/c nude hosts. Renca cells were transfected with the mammalian expression vector pCAGGS containing murine IL-4 cDNA or vector alone, then stable IL-4 transfectants (RencaL or RencaH, low- or high-IL-4-producing respectively) and control renca cells (RencaC) were obtained. RencaL cells, RencaH cells, or RencaC cells (1 x 10(5) each) were implanted into the subcapsule of the left kidney of Balb/c, Balb/c nude, and allogenic C3H/HeJ mice, then tumor formation was evaluated 14 days later. When RencaH cells were innoculated into syngeneic Balb/c hosts, tumor volume was marginally suppressed (P = 0.03) and tumors tended to be rejected (P = 0.06) compared with RencaC cells. However, those effects were not observed in Balb/c nude mice. RencaC, RencaL, and RencaH cells were not accepted by allogeneic C3H mice with or without FK506 administration or donor-specific transfusion. The administration of anti-(mouse IL-4) mAb to Balb/c mice significantly suppressed renca tumor growth by a CD4+ and CD8+ T-cell-dependent mechanism. By contrast, relatively high levels of IL-4 production by renca cells and T cells seemed to be required to induce the rejection and growth suppression of IL-4-producing renca cells in syngeneic hosts.

Animals↗

PubMed1997

Sequence variation of the rDNA ITS regions within and between anastomosis groups in Rhizoctonia solani.

Sequence analysis of the rDNA region containing the internal transcribed spacer (ITS) regions and the 5.8s rDNA coding sequence was used to evaluate the genetic diversity of 45 isolates within and between anastomosis groups (AGs) in Rhizoctonia solani. The 5.8s rDNA sequence was completely conserved across all the AGs examined, whereas the ITS rDNA sequence was found to be highly variable among isolates. The sequence homology in the ITS regions was above 96% for isolates of the same subgroup, 66-100% for isolates of different subgroups within an AG, and 55-96% for isolates of different AGs. In neighbor-joining trees based on distances derived from ITS-5.8s rDNA sequences, subgroups IA, IB and IC within AG-1 and subgroups HG-I and HG-II within AG-4 were placed on statistically significant branches as assessed by bootstrap analysis. These results suggest that sequence analysis of ITS rDNA regions of R. solani may be a valuable tool for identifying AG subgroups of biological significance.

Base Sequence↗

PubMed1997

Differences in factors associated with silent and symptomatic MRI T2 hyperintensity lesions.

The factors and symptomatology associated with different types of hyperintensity lesions on MRI were investigated. The study population consisted of 139 subjects who were recruited from 450 outpatients who had a neurological diagnosis in 1994. The subjects underwent brain magnetic resonance imaging between 1994 and 1995 and were divided into three groups (control, asymptomatic, and symptomatic) on the basis of T2 hyperintensity lesions, as well as a history of or neurological signs of stroke, or both. The demographic characteristics and risk factors were studied, and the T2 hyperintensity lesions were analysed semi-quantitatively. Results showed that: (1) the control and asymptomatic groups did not differ in terms of risk factors and demographic characteristics with the exception of age; (2) the symptomatic group was characterized by a significantly higher incidence of hypertension and electrocardiographic abnormalities, as well as significantly more numerous risk factors when compared with the other two groups; (3) the symptomatic patients also had higher proportion of men and higher levels of systolic blood pressure and blood glucose than the control patients, and more frequent hypertriglyceridaemia and higher triglyceride level than the asymptomatic patients; (4) the symptomatic group had a greater lesion distribution in the posterior basal ganglia-internal capsule and the infratentorial regions than did the asymptomatic group. We concluded that the asymptomatic and symptomatic groups should not be considered identical entities.

Aged↗

PubMed1997

Identification of Entamoeba histolytica and E. dispar cysts in stool by polymerase chain reaction.

An attempt to identify cysts of Entamoeba histolytica and E. dispar in human stool was conducted by polymerase chain reaction (PCR) using two sets of primers (p11 plus p12 and p13 plus p14) specific for either species of ameba. The cysts in stool specimens obtained from 12 infected individuals were concentrated, freeze-thawed, and treated with Triton X-100 before their examination by PCR. The results of PCR on the cysts were generally consistent with data obtained by PCR on ameba trophozoites hatched from the cysts, by zymodeme analysis, and by enzyme-linked immunosorbent assay (ELISA) and with clinical findings. This PCR was negative for the stool containing large numbers of cysts of either E. coli, E. hartmanni, or Giardia lamblia as well as for the stool specimens obtained from uninfected individuals. The ameba cyst in stool processed using the present method was effective for the PCR analysis even after 1 month of storage at 4 degrees C. The present PCR was sensitive enough to detect ten cysts of either of the amebae.

Animals↗

PubMed1997

Primary obsessional slowness: long-term findings.

Cases of slowness among patients who spent large amounts of time to perform daily activities were first reported in 1974, and described as primary obsessional slowness (POS). It was observed that it was neither obsessive thoughts nor compulsions that directly hindered their daily activities. However, in more than 20 years following the original report, the diagnostic independence of POS remains controversial, some insisting that obsessional slowness can be explained as secondary. The authors experienced four cases in Japan which share the same characteristics as the original cases. Long-term observation and treatment has led us to support the diagnostic independence of POS. Slowness remained after other accompanying symptoms of obsessive-compulsive disorder had been successfully treated, showing that the slowness of our patients was not secondary.

Activities of Daily Living↗

PubMed1997

Motion-reversal reveals two motion mechanisms functioning in scotopic vision.

We studied scotopic motion mechanisms, using a two-frame sinusoidal grating separated by various ISIs equated for mean luminance level. Perceived direction of displacement varied with both ISI and luminance. As luminance decreased, apparent motion reversal disappeared. This is predicted by a first-order motion model if the underlying temporal impulse response function varies from biphasic under photopic conditions to monophasic under scotopic conditions. Performance at long (but not short) ISIs depends upon stimulus contrast, suggesting there is also a scotopic feature-tracking mechanism. With isoluminant and high spatial frequency gratings, where the temporal impulse response function is monophasic, no motion reversal was observed.

Adaptation, Ocular↗