Biomedical subjects

Y Ito

Publications and source records attributed to Y Ito.

At least 235 records · Page 13Linked to original sources

PubMed2001

Gradient micropattern immobilization of EGF to investigate the effect of artificial juxtacrine stimulation.

To investigate the concentration effects of immobilized biosignal molecules by microscopic observation, a gradient micropattern immobilization technique using a photomask was devised. Epidermal growth factor (EGF) was chosen as the biosignal molecule and was conjugated with photoreactive polyallylamine. The EGF derivative was immobilized onto a polystyrene plate by UV irradiation in the presence of a gradient-micropattern photomask. Gradient micropattern immobilization of the EGF derivative on the polystyrene plate was confirmed by immunostaining with anti-EGF antibody. Chinese hamster ovary cells overexpressing EGF receptors were cultured on the micropatterned plate. Growth enhancement was observed only in dense EGF derivative immobilized regions. The present technique is useful for the investigation of concentration-dependent effects of immobilized biosignal molecules.

Animals↗

PubMed2001

Activation of c-Src gene product in hepatocellular carcinoma is highly correlated with the indices of early stage phenotype.

BACKGROUND/AIMS: The aim of this study was to investigate whether c-Src is involved in carcinogenesis and progression of human hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma. METHODS: We designed an immunohistochemical study using Clone 28, an antibody that specifically recognizes the activated form of c-Src. RESULTS: Hepatocytes in normal liver, chronic hepatitis with or without cirrhosis, atypical adenomatous hyperplasia, as well as bile ductular cells, and infiltrating mononuclear cells were all negative for immunohistochemical staining for the activated c-Src. Among 87 cases of HCC tested, 40 (46%) were positively stained for the activated c-Src, and this positive staining was inversely correlated with the Ki-67 labeling index (LI) (P = 0.0031), intrahepatic metastasis (P = 0.0099), TNM stage (P = 0.0062), alpha-fetoprotein (P = 0.0103) and epidermal growth factor-receptor expression (P = 0.0153). Positive staining for the activated c-Src was more frequently observed in well- or moderately-differentiated carcinoma (P = 0.0256). In multivariate analysis, the activated c-Src expression was independently related to the Ki-67 LI (P = 0.0197). In contrast to positive staining in HCC, cholangiocarcinoma were classified as negative in all 19 cases examined. CONCLUSIONS: These results strongly suggest the involvement of activated c-Src in early stages of HCC, and suggest that cholangiocarcinoma might employ different signaling mechanisms.

Carcinoma, Hepatocellular↗

PubMed2001

Observation of oxygen vacancy ordering and segregation in perovskite oxides.

Oxygen vacancies are known to dominate the overall electrical behavior of perovskite oxides, which are used in many applications. Although theories have been developed to explain the effect of these vacancies and the defect chemistry of perovskites, there has yet to be incontrovertible evidence of the fundamental origins of the structure-property relationship. However, recently developed technologies in scanning transmission electron microscopy, such as Z-contrast imaging and EELS combined with in-situ heating experiments, provide a new opportunity to address vacancy characteristics and defect chemistry on the basic atomic level. In this paper we discuss the practical aspects of these techniques and demonstrate their application to the characterization of defect chemistry and vacancies in ordered micro-domains, at domain boundaries and at grain boundaries.

Journal Article↗

PubMed2001

Noninvasive quantitative tissue characterization and two-dimensional color-coded map of human atherosclerotic lesions using ultrasound integrated backscatter: comparison between histology and integrated backscatter images.

OBJECTIVES: The purpose of the present study was to define clinicopathologically whether integrated backscatter (IB) combined with conventional two-dimensional echo (2DE) can differentiate the tissue characteristics of calcification (CL), fibrosis (FI), lipid pool (LP) with fibrous cap, intimal hyperplasia (IH) and thrombus (TH) and can construct two-dimensional tissue plaque structure in vivo. BACKGROUND: It is difficult to characterize the components of plaque using conventional 2DE techniques. METHODS: Integrated backscatter values of plaques were measured in the right common carotid and femoral arteries (total 24 segments) both during life and after autopsy in 12 patients (age 68 to 84 years, 10 men and two women). Integrated backscatter values were determined using a 5-12 MHz multifrequency transducer, setting the region of interests (ROIs) (11 x 11 pixels) on the echo tomography of the entire arterial wall (55 +/- 10 ROI/segment) and comparing it with histologic features in the autopsied arterial specimens. RESULTS: Corrected IB values obtained before death and at autopsy were significantly correlated (r = 0.93, p < 0.01). Corresponding to the histologic features, corrected IB values on the rectangle ROIs obtained during life were divided into five categories: category 1 (TH) 4 < IB < or = 6; category 2 (media and IH or LP in the intima) 7 < IB < or = 13; category 3 (FI) 13 < IB < or = 18, category 4 (mixed lesion) 18 < IB < or = 27 and category 5 (CL) 28 < IB < or = 33. In category 2, media and intima were differentiated using conventional 2DE. Under the above procedures, color-coded maps constructed with IB-2DE obtained during life precisely reflected the histologic features of media and intima. CONCLUSIONS: Integrated backscatter with 2DE represents a useful noninvasive tool for evaluating the tissue structure of human plaque.

Aged↗

PubMed2001

The chondrogenic potential of periosteum decreases with age.

Periosteum contains undifferentiated mesenchymal stem cells that possess the potential for chondrogenesis during cartilage repair and in fracture healing. With aging, the chondrogenic potential of periosteum declines significantly. An organ-culture model was used to investigate the relationship between the chondrogenic potential of periosteum and aging. A total of 736 periosteal explants from the proximal medial tibiae of 82 rabbits, aged 2 weeks to 2 years, were cultured in agarose suspension conditions conductive for chondrogenesis. and analyzed using histomorphometry, collagen typing, wet weight measurement, 3H-thymidine and 35S-sulfate uptake, autoradiography, and PCNA immunostaining. The rabbits were skeletally mature by 6 months and stopped increasing in weight by 12 months. Chondrogenesis declined significantly with age (P < 0.0001) and was maximal in the 1.5-2 month-old rabbits. Explants from the 6 month-old rabbits formed 50% less cartilage. and by 12 months chondrogenesis reached a steady state minimal level. In parallel with this decrease in chondrogenic potential similar decreases were measured in 3H-thymidine uptake (P < 0.0001). 35S-sulfate uptake (P = 0.0117), as well as the thickness (P < 0.0001) and the total number of cells in the cambium layer of the periosteum (P < 0.0001). Autoradiography with 3H-thymidine and PCNA immunostaining confirmed the measured decrease in proliferative activity in the cambium layer where the chondrocyte precursors reside, although the percentage of proliferating cells did not change significantly with age. The most dramatic change was the marked decrease (87%) in the thickness and total cell number in the cambium layer of the perisoteum between the 2 and 12 month-old rabbits (P < 0.05). These data confirm a decline in the chondrogenic potential of periosteum with aging. Thus, one possibility for improving cartilage formation by periosteal transplantation after skeletal maturity would be to stimulate an increase in the total number of cells in the chondrocyte precursor pool early during chondrogenesis.

Age Factors↗

PubMed2001

Histomorphological and proliferative characterization of developing periosteal neochondrocytes in vitro.

Periosteal chondrogenesis is relevant to cartilage repair and fracture healing. Cell proliferation is a limiting factor of cartilage production. We used an in vitro organ culture model to test the hypothesis that proliferative activity correlates with cell morphology. One hundred and four periosteal explants from 26 two-month old New Zealand rabbits were cultured for up to 42 days. They were analyzed histomorphologically, and immunohistochemically with proliferative cell nuclear antigen (PCNA). The periosteal neocartilage displayed a consistent zonal pattern of chondrocyte cell shapes. The flat cell zone from day 7 to 21, consisted of uniform-sized small spindle-shaped cells. The round cell zone, which appeared on day 14, consisted of variable-sized round cells averaging 510 +/- 250 microm2 in area. They were subdivided into small round (<510 microm2) and large round cells (>510 microm2). The proliferative index was highest in the small round cell group (32 +/- 6%), intermediate in the flat cell group (27 +/- 6%), and lowest in the large round cell group (20 +/- 7%) (P < 0.001). Furthermore, the proliferative indices in the round cell group were inversely proportional to cell size. Therefore, (1) there is a sequential progression of cell morphology during periosteal chondrogenesis, (2) cell differentiation is arrested prior to terminal differentiation for some cells and not for others, and (3) proliferative activity is strongly related to cell morphology. This organ culture model provides us with opportunities to study the regulation of terminal chondrocyte differentiation and the control of cell proliferation. This will contribute to our understanding of cartilage repair, fracture healing and growth plate physiology.

Animals↗

PubMed2001

Cloning and expression pattern of a novel PEBP2 beta-binding protein (charged amino acid rich leucine zipper-1[Crl-1]) in the mouse.

PEBP2 beta/Cbf beta is the beta subunit of PEBP2/Cbf, which has been demonstrated to have important biological activities in hematopoiesis and osteogenesis. However, PEBP2 beta is ubiquitously expressed, suggesting that PEBP2 has other additionally important physiological activities. In an effort to elucidate other possible functions for PEBP2, we have isolated a novel gene that encodes a PEBP2 beta-interacting protein from a mouse cDNA library. We have called this gene Crl-1 for charged amino acid rich leucine zipper-1 (Crl-1) because it is rich in charged amino acids and contains a putative leucine zipper region. Expression studies in a 17.5 days post-coitum mouse embryo demonstrated Crl-1 expression mainly in the olfactory bulb and cerebral cortex. Post-natally, Crl-1 expression was additionally observed in the cerebellar cortex with strong expression in the hippocampus. These findings show that this novel PEBP2 beta-interacting protein is expressed mainly in subsets of neuronal cells, suggesting that Crl-1 plays some role in the developing mouse brain.

Amino Acid Sequence↗

PubMed2001

CD4+ T cells are required for HSP65 expression in host macrophages and for protection of mice infected with Plasmodium yoelii.

We have reported that macrophages expressing heat-shock protein 65 play an essential role in protection of mice infected with Plasmodium yoelii. In this study, we investigated the function and expression mechanism of HSP65 in macrophages of mice infected with P. yoelii. C57BL/6 (B6) mice are susceptible to infection with the lethal (L) strain but resistant to infection with the non-lethal (NL) strain of P. yoelii. The percentage of apoptotic macrophages in mice infected with the L strain was higher than that in mice infected with the NL strain. However, the percentage was low in L strain infected mice if they acquired resistance to the infection by primary infection with the NL strain. That apoptosis was reversely correlated with HSP65 expression in splenic macrophages from mice infected with P. yoelii suggests HSP65 may contribute to protective immunity by preventing apoptosis of macrophages in malarial infection. Cell depletion/transfer experiments showed that CD4+ T cells, but not CD8+ T cells, gammadelta T cells, NK cells or NK T cells, were required for HSP65 expression in macrophages as well as for protection of mice infected with P. yoelii. In conclusion, HSP65 may play a role in preventing apoptosis of macrophages in mice infected with P. yoelii. CD4+ T cells are required for HSP65 expression and for protective immunity against P. yoelii infection.

Animals↗

PubMed2001

In vitro selection of nonnatural ribozyme-catalyzing porphyrin metalation.

A new macromolecular catalyst, which is composed of nonnatural ribonucleotide, was synthesized by the in vitro selection (SELEX) method. A pool of RNAs consisting of random sequences was obtained by transcription from a pool of synthetic random-sequence DNAs in the presence of 2'-aminocytidine triphosphate (2'-amino-CTP) instead of CTP. The pool was incubated with N-methylmesoporphyrin-immobilized gel; bound nonnatural RNAs were then collected and amplified by reverse-transcription following the polymerase chain reaction. The amplified DNAs were again transcribed in the presence of 2'-amino-CTP and applied to the gel. This selection process was repeated 10 times. The selected RNAs were cloned and sequenced. The RNAs not only bound to the ligand, N-methylmesoporphyrin but also catalyzed the metalation reaction of porphyrin.

Base Sequence↗

PubMed2001

Centrifugal precipitation chromatography -- a novel chromatographic system for fractionation of polymeric pigments from black tea and red wine.

A novel chromatographic system was developed and first applied to the fractionation of polymeric pigments from black tea and red wine. Centrifugal precipitation chromatography (CPC) generates solvent gradients through a long separation channel under a centrifugal force field. Tea and wine extracts are precipitated in a hexane- or methyl tert-butyl ether-rich environment and are exposed to a gradually increasing ethanol concentration. This causes a repetitive precipitation and dissolution of the biopolymers along the channel. Consequently, they are eluted in the order of their solubility in the organic solvent. It is shown by HPLC analysis of the separated fractions that monomers elute first, whereas fractionated polymers can be found at the end of the chromatographic run. This novel method allows gentle fractionation of polymeric tea and wine constituents and also has potential for use in preparative-scale separations.

Centrifugation↗

PubMed2001

Expression of mRNAs for ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), interleukin-6 (IL-6), and their receptors (CNTFR alpha, LIFR beta, IL-6R alpha, and gp130) in human peripheral neuropathies.

The mRNA levels of neuropoietic cytokines, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), and interleukin-6 (IL-6), and their receptor components (CNTFR alpha, LIFR beta, IL-6R alpha, and gp130) were examined in seventy-six patients with various peripheral neuropathies to determine the extent of expression of these cytokines and receptors, and their relationship to nerve fiber pathology and cell infiltration in the diseased nerves. The CNTF mRNA levels were significantly decreased in the diseased nerves and were correlated to residual myelinated fiber population. In contrast, the mRNA levels of LIF, IL-6 and the ligand-binding receptor components (CNTFR alpha, LIFR beta and IL-6R alpha) were elevated to variable extent in the diseased nerves. The CNTFR alpha, LIFR beta, and IL-6R alpha mRNA levels showed a weak positive correlation with the extent of demyelinating pathology and their levels were related to each other. Moreover, the CNTF and LIF mRNA levels were inversely proportional to the extent of macrophage invasion, whereas the CNTFR alpha and IL-6R alpha mRNA expressions were correlated to the increase in macrophage infiltration. The neuropoietic cytokine family and its receptor expressions in the diseased human nerves are regulated by an underlying pathology-related process rather than type of diseases, and could play a role in peripheral nerve regeneration and repair.

Adult↗

PubMed2001

Fas ligand expression in BRCA1-associated hereditary breast carcinoma clearly differs from that in sporadic breast carcinoma.

BRCA1-associated hereditary breast carcinomas (HBCs) are diagnosed at a younger age and are known to show biological aggressiveness such as a high histological grade, frequent aneuploidy, compared to sporadic breast carcinomas. However, results of studies on their prognosis have been controversial. We hypothesized that some factors such as a high incidence of cell death could offset the aggressiveness of BRCA1-associated HBCs, and therefore investigated Fas and Fas ligand (Fas L) expression in 19 BRCA1-associated HBCs and 56 age-adjusted control cases. Glandepithelial and myoepithelial cells in the mammary glands expressed Fas in high incidence, but all were negative for Fas L. Fas was expressed in 89.5% of BRCA1-associated HBCs and 94.4% of the controls and no significant differences could be established between the two groups. However, in 73.7% of BRCA1-associated HBCs, Fas L was clearly expressed in the infiltrating mononuclear cells, whereas this was observed in only 14.3% of the control cases and statistical significance was established between the two groups (p < 0.0001). These results strongly suggest that carcinoma cells in BRCA1-associated HBCs are more likely to be attacked by mononuclear cells via Fas L, and this may explain, at least in part, the discrepancy with respect to the prognosis. On the other hand, carcinoma cells also expressed Fas L significantly more often (p < 0.0001) in BRCA1-associated HBCs (52.6%) than in sporadic cases (3.6%). This can be considered a kind of counterattack against the mononuclear cells or, alternatively, may enhance the Fas-Fas L pathway in an autocrine/paracrine fashion. The clinical significance of Fas L expressing carcinoma cells remains to be elucidated.

Adult↗

PubMed2001

Expression of heparin-binding epidermal growth factor-like growth factor in breast carcinoma.

The expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) was investigated for 76 cases of breast carcinoma. HB-EGF was expressed in 71.8% of the carcinoma cases but only slightly in normal mammary glands. Interestingly, its expression was inversely related to biological aggressiveness of the breast carcinoma. These results suggest that HB-EGF may play a crucial role in the early stage of this carcinoma.

Adult↗

PubMed2001

In vivo gene electroporation of glial cell line-derived neurotrophic factor (GDNF) into skeletal muscle of SOD1 mutant mice.

Motor neurons degenerate with intracellular vacuolar change and eventually disappear in spinal cords of SOD1 mutant mice, resembling human amyotrophic lateral sclerosis (ALS). The GDNF gene was electroporatically transferred into the leg muscles of SOD1 mutant mice and expressed in muscle cells. This gene therapy with GDNF delayed the deterioration of motor performance, being retrogradely transported into spinal motor neurons. However, the number of the motor neurons and survival of the mutant mice were not improved by GDNF treatment. These results indicate that in vivo gene electroporation of GDNF into muscles could be an appropriate therapeutic approach to ameliorate an early dysfunction of motor neurons in SOD1 mutant mice, but further improvement is needed to use this gene transfer as an effective treatment of ALS.

Animals↗

PubMed2001

A seroepidemiological study of the risks of Q fever infection in Japanese veterinarians.

The causative agent of Q fever, a widespread zoonotic disease, is the bacteria Coxiella burnetii. Although cases of Q fever have been documented in countries throughout the world, the prevalence of the disease in Japan is not yet known. Q fever is a demonstrated occupational hazard to those employed in zoological professions, but the risk to Japanese veterinarians has not yet been quantified. In order to evaluate the risk to Japanese veterinarians, we performed a serological survey using serum samples from 267 veterinarians. Two control groups consisting of 352 medical workers and 2003 healthy blood donors were also evaluated. The antibody titers of the serum samples were measured by indirect immunofluorescence assay (IFA) using phase II C. burnetii Nine Mile strain as the antigen. The positive rate of IgG antibody was 13.5% in the veterinarians, which was higher than in the blood donors (3.6%, p < 0.001) and medical workers (5.1 %,p < 0.001). These findings suggest that Japanese veterinarians have a higher risk of infection by C. burnetii than other members of the Japanese population. An interesting finding of this study was that positive rates of IgG and IgM antibodies in the blood donor group were higher in younger individuals. The IgM antibody positive rate was the highest in females under 30 years old.

Antibodies, Bacterial↗

PubMed2001

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT): initial aims and impact of the family history of type 1 diabetes mellitus in Japanese children.

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) was established in July 1994 with the chief aim to improve the quality of therapy for type 1 diabetes in children, an entity far less common in Japan than in Europe. We proposed four initial research topics: (i) to determine the current status of medical care and glycemic control in Japanese children with type 1 diabetes mellitus; (ii) to standardize the measurement of hemoglobin A1c; (iii) to establish a registry of a large cohort of patients in order to enable prospective studies to improve the quality of therapy for children with type 1 diabetes in Japan; and (iv) to enable participants of the JSGIT to hold a workshop twice annually. We registered a total of 736 patients from 45 hospitals throughout Japan. Intervention via insulin treatment was instituted after 2 yr for those patients whose hemoglobin A1c level was more than 8.1%. The proportion of patients receiving multiple insulin injections increased after intervention; however, average hemoglobin A1c in females remained significantly higher than in males. We identified two forms of diabetes in Japanese children: a rapidly progressive form and a more slowly progressive form. There was a significantly higher prevalence of a family history of diabetes in first-degree relatives in the slowly progressive form. These preliminary findings are the result of the first collaborative study of childhood diabetes in Japan.

Journal Article↗

PubMed2001

Serum antioxidant micronutrient levels in oral lichen planus.

The aim of this study was to elucidate any association between oral lichen planus (OLP) and serum antioxidant micronutrients by a population-based case-control study. A total of 9536 subjects were examined, and 62 (58 reticular, 4 atrophic and erosive) diagnosed with OLP at referral facilities were compared with four controls per case (n=248) selected among disease-free subjects matched for age and sex. Serum levels of micronutrients (retinol, alpha-tocopherol, zeaxanthin/lutein and cryptoxanthin, lycopene, alpha-carotene and beta-carotene) were estimated by the high performance liquid chromatography (HPLC) method. Among cases, mean serum retinol level (2.820+/-0.849 micromol/l) was significantly higher compared with that of controls (2.562+/-0.735 micromol/l) (P<0.05). No significant differences were noted in carotenoid levels examined in this study, except for a lower level of lycopene found in atrophic/erosive OLP cases. The results of this study suggest that low serum retinol or carotenoid levels are not risk factors for occurrence of lichen planus, and any specific benefits of antioxidant micronutrients cannot be claimed for this inflammatory disorder.

Adult↗

PubMed2001

Suppression of CCR5- but not CXCR4-tropic HIV-1 in lymphoid tissue by human herpesvirus 6.

HIV-1 infects target cells via a receptor complex formed by CD4 and a chemokine receptor, primarily CCR5 or CXCR4 (ref. 1). Commonly, HIV-1 transmission is mediated by CCR5-tropic variants, also designated slow/low, non-syncytia-inducer or macrophage-tropic, which dominate the early stages of HIV-1 infection and frequently persist during the entire course of the disease. In contrast, HIV-1 variants that use CXCR4 are typically detected at the later stages, and are associated with a rapid decline in CD4+ T cells and progression to AIDS (refs. 2,7-11). Disease progression is also associated with the emergence of concurrent infections that may affect the course of HIV disease by unknown mechanisms. A lymphotropic agent frequently reactivated in HIV-infected patients is human herpesvirus 6 (HHV-6), which has been proposed as a cofactor in AIDS progression. Here we show that in human lymphoid tissue ex vivo, HHV-6 affects HIV-1 infection in a coreceptor-dependent manner, suppressing CCR5-tropic but not CXCR4-tropic HIV-1 replication, as shown with both uncloned viral isolates and isogenic molecular chimeras. Furthermore, we demonstrate that HHV-6 increases the production of the CCR5 ligand RANTES ('regulated upon activation, normal T-cell expressed and secreted'), the most potent HIV-inhibitory CC chemokine, and that exogenous RANTES mimics the effects of HHV-6 on HIV-1, providing a mechanism for the selective blockade of CCR5-tropic HIV-1. Our data suggest that HHV-6 may profoundly influence the course of HIV-1 infection.

Chemokine CCL5↗