Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 55 records · Page 3Linked to original sources

PubMed2001

Occurrence of ovalbumin in ovarian yolk of chicken during oogenesis.

Yolk specimens from chicken ovaries during oogenesis gave a positive signal for ovalbumin as analyzed by Western blotting, indicating that the ovarian yolk contains ovalbumin. Northern blotting and reverse transcriptase-polymerase chain reaction gave a negative signal for ovalbumin mRNA in the liver and other organs except oviduct, whereas the laying hen serum was found to indicate immunologically the presence of ovalbumin. It was therefore assumed that ovalbumin synthesized in the oviduct might partly be secreted into the blood circular system, from which it is taken up into the oocyte.

Animals↗

PubMed2001

The N- and C-terminal regions of RBP-J interact with the ankyrin repeats of Notch1 RAMIC to activate transcription.

The evolutionarily-conserved DNA-binding protein RBP-J directly interacts with the RAM domain and the ankyrin (ANK) repeats of the Notch intracellular region (RAMIC), and activates transcription of downstream target genes that regulate cell differentiation. In vitro binding assays demonstrate that the truncated N- and C-terminal regions of RBP-J bind to the ANK repeats but not to the RAM domain. Using an OT11 mouse cell line, in which the RBP-J locus is disrupted, we showed that RBP-J constructs mutated in the N- and C-terminal regions were defective in their transcriptional activation induced by either RAMIC or IC (the Notch intracellular region without the RAM domain) although they had normal levels of binding activity to DNA and the RAM domain. The studies using chimeric molecules between RBP-J and its homolog RBP-L showed that the N- and C-terminal regions of RBP-J conferred the IC- as well as RAMIC-induced transactivation potential on RBP-L, which binds to the same DNA sequence as RBP-J but fails to interact with RAMIC. Taken together, these results indicate that the interactions between the N- and C-terminal regions of RBP-J and the ANK repeats of RAMIC are important for transactivation of RBP-J by RAMIC.

Animals↗

PubMed2001

Functional pleiotropy of an intramolecular triplex-forming fragment from the 3'-UTR of the rat Pigr gene.

A microsatellite-containing 359-bp restriction fragment, isolated from the rat Pigr gene (murine polymeric immunoglobulin receptor gene) 3'-untranslated region (3'-UTR) and inserted into 3'-UTR or 3' flanking positions in transcription units of supercoiled plasmids, attenuates luciferase reporter gene expression in orientation- and position-dependent ways following transient transfection of human 293 cells. The same fragment stimulates orientation-dependent gene expression in a 5' flanking position. Plasmid linearization abrogates both orientation- and position-dependent responses. Cell-free translation reveals that 5' and 3' flanking expression responses are proportional to increased and decreased luciferase mRNA levels, whereas 3'-UTR expression is associated with control mRNA levels. Hypersensitivity to nucleases S1 and P1, gel mobility differences between supercoiled plasmids carrying opposing microsatellite orientations, and anomalous melting profiles of this fragment are also observed. These results suggest that functional pleiotropy of this fragment depends on the DNA context of its purine-rich microsatellite strand and on DNA supercoiling. Intramolecular triplexes stabilized by supercoiling and secondary structures of purine repeat-rich mRNAs may also confer regulatory properties to similar genomic elements.

3' Untranslated Regions↗

PubMed2001

Effects of fluvoxamine on morphine-induced inhibition of gastrointestinal transit, antinociception and hyperlocomotion in mice.

In the present study, the effects of fluvoxamine on the inhibition of gastrointestinal transit, antinociception and hyperlocomotion induced by morphine were investigated in mice. Treatment with morphine (10 mg/kg, subcutaneously (s.c.)) inhibited gastrointestinal transit and hyperlocomotion. These effects were attenuated by fluvoxamine in a dose-dependent manner. On the other hand, morphine (1 mg/kg, s.c.)-induced antinociception was significantly potentiated by fluvoxamine. These results suggest that fluvoxamine combined with morphine may be useful for the treatment of not only depression but also pain in cancer patients without constipation or activation of the mesolimbic dopaminergic system. However, further understanding and clinical studies will be required to confirm this possibility.

Analgesics, Opioid↗

PubMed2001

The use of a permanent magnetic resonance imaging system for radiotherapy treatment planning of bone metastases.

PURPOSE: To evaluate the usefulness of magnetic resonance (MR) imaging-based radiotherapy treatment planning (RTTP) for bone metastases in clinical applications. METHODS AND MATERIALS: MR imaging-based RTTP was carried out for 28 patients with bone metastases using a permanent magnetic MR unit. Twenty-three patients received MR imaging-assisted X-ray simulation, and five underwent MR simulation. In MR imaging-assisted X-ray simulation, the radiation fields defined by an X-ray simulator were modified based on MR information scanned in the exact treatment position using MR skin markers. In MR simulation, both isocenter position and field size were determined on MR images and projected onto the patient's skin. RESULTS: All lesions unclear on other imaging modalities could be clearly identified on MR imaging. Of the 23 patients receiving MR imaging-assisted X-ray simulation, modification of the original radiation field was necessary in 14 patients (extended in 9, reduced in 4, and completely changed in 1). In MR simulation, appropriate radiation fields could be easily and quickly determined using MR imaging. CONCLUSION: Methods for MR imaging-based RTTP were developed and clinically implemented for patients with bone metastases, and they were shown to be useful for improving the accuracy of the tumor location. They would provide better therapeutic/palliative benefit to particular patients with bone metastases and could also be applied to other lesions in the future.

Adult↗

PubMed2001

Evaluation of glass microspheres for intra-arterial radiotherapy in animal kidneys.

PURPOSE: To evaluate the histologic distribution of nonradioactive microspheres when intra-arterially infused into normal kidneys, and to evaluate the histologic changes after the infusion. MATERIALS AND METHODS: The glass microspheres were SiO2 microspheres with a smooth spherical shape measuring 20-30 micrometers in diameter with a specific gravity of 2.2 g/cm3. After the microspheres were mixed with contrast medium, they were infused into the renal artery. Twelve rabbits were sacrificed at 1 day, 3 days, 1 week, and 8 weeks after the treatment, respectively. The specimen was fixed with 10% buffered formalin, specially embedded in methyl methacrylate (MMA) resin and was stained by hematoxylin-eosin. The distribution of the microspheres in the kidney was analyzed microscopically, and histologic changes were also evaluated. RESULTS: The microspheres were found in arterioles whose diameters were about 20-30 micrometers, within normal kidneys. All vessels containing microspheres were confined to arterioles or arteries. No migration of microspheres was detected in the normal lung or the contralateral kidney. Severe ischemic changes were observed in kidneys, developing within 8 weeks of the infusion. CONCLUSION: Glass microspheres seemed to be a useful embolic material for intra-arterial radiation therapy.

Animals↗

PubMed2001

Effect of methylprednisolone on the kinetics of cytokines and liver function of regenerating liver in rats.

The participation of cytokines in the early stage mechanism of hepatocyte proliferation has already attracted attention. We investigated the effect of methylprednisolone (MDS), which inhibits the inflammatory response, given before and after a 70% partial hepatectomy in rats on the kinetics of tumor necrosis factor-alpha and Interleukin-6, liver cell function and the rate of liver regeneration. Serum Interleukin-6 levels of the MDS groups were significantly lower than those of the control group. Serum alanine aminotransferase, aspartate aminotransferase and hyaluronic acid levels were also significantly decreased, however, the serum albumin level showed high values in the MDS groups. In the MDS groups, MIB-5 labeling indices, a novel antibody reactive with the equivalent Ki-67 protein, which detects immunohistochemically all active parts of the cell cycle in the rat liver, were more pronounced than in the control group at an earlier time. However, in regard to 5-bromo-2-deoxyuridine (BrdU), there were no significant differences among the three groups. There were no differences in residual liver weight/body weight between the three groups after 336 h. In our study, MDS administration before or after a 70% partial hepatectomy decreased serum Interleukin-6 levels, and inhibited hepatic dysfunction. Therefore, we considered that beneficial effects of physiological doses of MDS in the peri-operative period should be confirmed in humans.

Journal Article↗

PubMed2001

One hundred consecutive treatments with holmium: YAG laser for pulmonary bullae: especially in conjunction with gelatin-resorcinol formaldehyde-glutaraldehyde glue adhesion.

BACKGROUND AND OBJECTIVE: We have widely used a Ho:YAG laser to treat bullae thoracoscopically. STUDY DESIGN/MATERIALS AND METHODS: Bullae with broad necks were treated with a Ho:YAG laser thoracoscopically. Because one patient relapsed after application of fibrin glue in the early period, a DEXON (polyglycolic acid) mesh patch soaked in fibrin glue was used through a 2-cm opening in the subsequent cases. Lastly, gelatin-resorcinol formaldehyde-glutaraldehyde (GRFG) glue was applied through a 5-mm opening instead of a DEXON mesh after coagulation. RESULTS: In the 38 patients patched with DEXON mesh soaked in fibrin glue and 56 patched with GRFG glue after coagulation, none relapsed. CONCLUSION: Combined uses of fibrin glue plus DEXON mesh or GRFG glue were effective when bullae were treated with the Ho:YAG laser. However, the wound was smaller and more cosmetic in the GRFG glue group than in the DEXON mesh plus fibrin glue group.

Blister↗

PubMed2001

Comparison of plastic prostheses and self-expandable metallic stents in the treatment of malignant esophageal stenosis.

OBJECTIVE: We compared the efficacy of plastic prostheses and self-expandable metallic stents in the treatment of malignant esophageal stenosis and/or fistula. SUBJECTS AND METHODS: Subjects were 31 patients with esophageal cancer, 4 with esophagotracheal fistula, and 1 with esophageal stenosis. A plastic prosthesis was inserted in 15 patients (group A) and a self-expandable metallic stent in 21 patients (group B). We evaluated food ingestion improvement, effectiveness, complications, mean survival, food ingestion duration, the percentage of food ingestion capability in total survival time, and inhospital mortality. RESULTS: No differences were seen in food intake improvement or in the effectiveness between groups, whereas fatal complications were higher in Group A. No significant differences were seen in mean survival, food ingestion duration, percentage of food ingestion capability, or inhospital mortality between groups. CONCLUSION: We concluded that a self-expandable metallic stent was safer than a plastic prosthesis because of fewer serious complications such as bleeding, and recommended the use of metallic stents in the treatment of malignant esophageal stenosis and/or fistula.

Aged↗

PubMed2001

Cloning of Japanese flounder Paralichthys olivaceus CD3 cDNA and gene, and analysis of its expression.

Two distinct CD3 homologue cDNAs, CD3-1 and CD3-2, were isolated from a Japanese flounder leukocyte cDNA library. CD3-1 consisted of 961 bp encoding 178 amino acid residues, and CD3-2 consisted of 927 bp encoding 182 amino acid residues. The two deduced amino acid sequences had an identity of 95.1%, and neither had N-linked glycosylation sites. The identities between the Japanese flounder CD3s and previously reported CD3s (CD3 epsilon, CD3 gamma, or CD3 delta) of Xenopus laevis, chicken, and various mammals were approximately 25%. The Japanese flounder CD3s had an extracellular domain, a CXXCXE motif, and an immunoreceptor tyrosine-based activation motif (ITAM), each of which are important characteristics of CD3 chains. Furthermore, the positions of four cysteine residues in the extracellular domain were preserved in both of the Japanese flounder CD3s. A phylogenetic tree based on the amino acid sequences confirmed that the Japanese flounder CD3s are closer to CD3 epsilon than to CD3 gamma and CD3 delta. However, the gene structure of Japanese flounder CD3 is identical to the chicken and Xenopus CD3 gamma/delta genes and the mammalian CD3 delta gene. Southern blot hybridization and the DNA sequence of the CD3 gene of homocloned Japanese flounder indicated that the CD3 gene exists as a single copy. Southern blot hybridization also showed the presence of a polymorphic variant of Japanese flounder CD3. An RT-PCR analysis detected Japanese flounder CD3 mRNA in several organs that contained lymphocytes. The proportion of CD3-positive cells in the peripheral blood leukocytes was 34.9%.

Amino Acid Sequence↗

PubMed2001

Anti-transforming growth factor-beta1 antibody transiently enhances DNA synthesis during liver regeneration after partial hepatectomy in rats.

The regulation of liver regeneration after partial hepatectomy (PHx) is complex and involves many different cytokines. We investigated the role of one of these, transforming growth factor-beta1 (TGF-beta1), an inhibitor of liver regeneration, in a Wistar male rat model, in which anti-TGF-beta1 antibody was injected immediately or 24 h after 70% PHx. Livers from treated animals contained an increased number of cells in S phase, according to 5-bromo-2'-deoxyuridine (BrdU) labeling 36 h after PHx. Antibody administration 24 h after PHx resulted in the highest peak of proliferation; moreover, peak MIB-5 labeling was also observed at that time. However, neither residual liver-weight-to-body-weight ratios nor regeneration rates differed significantly between any of the animals. Therefore, we also measured levels of serum TGF-beta1 and hepatocyte growth factor (HGF; an activator). With antibody administration at 0 or 24 h, TGF-beta1 levels were diminished at 24 or 36 h as compared with levels in control rats, but then rebounded, reaching a delayed peak at 48 or 72 h after PHx, respectively. Interestingly, there were also similar trends in HGF levels. These results indicate that TGF-beta1 may inhibit the G1 checkpoint, and serum TGF-beta1 concentration may influence HGF to regulate liver regeneration and to maintain homeostasis of proliferation after PHx.

Analysis of Variance↗

PubMed2001

Effect of extracellular calcium on the gene expression of bone morphogenetic protein-2 and -4 of normal human bone cells.

A high extracellular calcium level inhibits the formation of osteoclast-like cells and stimulates osteoblastic proliferation, indicating that extracellular calcium plays an important role in the process of bone remodeling. The present study examined the effects of a high extracellular calcium level on mRNA levels of bone morphogenetic protein (BMP)-2 and -4, which are well-documented osteoinductive proteins, and the differentiation of normal human mandible-derived bone cells in vitro. High extracellular calcium significantly increased cell proliferation at an optimal dose of 0.4mM CaCl2 added to control medium containing 1.8 mM CaCl2. The addition of 0.1-0.4mM CaCl2 markedly increased the mRNA levels of BMP-2 and -4 following incubation for 0.5 and 24 h as evaluated by reverse transcription-polymerase chain reaction. While an increased extracellular calcium level (addition of 0.1-1.2mM CaCl2) failed to increase alkaline phosphatase activity and osteocalcin secretion, it did significantly increase type I collagen synthesis, monitored by the production of procollagen type I carboxy-terminal peptide. These results indicate that the extracellular calcium level regulates BMPs and type I collagen synthesis in osteoblastic cells.

Adult↗

PubMed2001

Complications associated with pulmonary resection in lung cancer patients on dialysis.

BACKGROUND: There are few studies available investigating the perioperative problems experienced by lung cancer patients on dialysis undergoing pulmonary resection. METHODS: A retrospective review of 7 patients on dialysis undergoing pulmonary resection for lung cancer was performed. RESULTS: The patient population consisted of 7 men, with a mean age of 59.9 years. The underlying kidney disease was glomerulonephritis in 5 patients and nephrosclerosis in 2. The mean levels of blood urea nitrogen and serum creatinine were 70.7 mg/dL and 9.4 mg/dL, respectively. Histologic diagnoses were adenocarcinoma in 2 patients and squamous cell carcinoma in 5. Standard lobectomy with lymph node dissection was performed in all cases. There was one operation related death due to pulmonary edema and subsequent development of pneumonia. There were two cases of sputum retention and four of hyperkalemia. One patient died of cerebral bleeding that occurred during dialysis 2 months postoperatively. CONCLUSIONS: In patients on dialysis who undergo pulmonary resection, there is a high incidence of pulmonary complications, in addition to hyperkalemia, hemodynamic instability, and a tendency for postoperative dialysis-associated bleeding.

Adenocarcinoma↗

PubMed2001

Early results of a prospective study of limited resection for bronchioloalveolar adenocarcinoma of the lung.

BACKGROUND: We reported that bronchioloalveolar adenocarcinoma (BAC) without active fibroblastic proliferation of the lung had no lymph node and pulmonary metastasis and had a favorable prognosis. However, there has been no prospective trial regarding limited pulmonary resection for this type of BAC. The purpose of this study is to confirm the effectiveness of limited resection for histologically confirmed BAC without active fibroblastic proliferation. METHODS: From 1996 through 1999, 42 patients who had small peripheral lung tumors (< or = 20 mm), suspected of being BAC, were enrolled in this trial. The patient population consisted of 24 men and 18 women with a mean age of 58.4 years. Limited resection was completed when BAC, without both active fibroblastic proliferation and lymph node metastasis, was confirmed histologically by intraoperative pathologic examination. RESULTS: Limited resection was completed in 36 patients, wedge resection in 34, and segmentectomy in 2 patients. In 6 patients, the procedure was converted into lobectomy because of pathologic invasive sign in 3, active fibroblastic proliferation in 1, and for other reasons in 2 patients. All patients have been followed for a median follow-up period of 30 months and are alive without sign of recurrence. CONCLUSIONS: Our early results indicate that limited resection may be an acceptable alternative to lobectomy for histologically confirmed BAC without active fibroblastic proliferation.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2001

Callosal commissural neurons of Dab1 deficient mutant mouse, yotari.

The yotari mouse is an autosomal recessive mutant mouse, caused by mutation of disabled homolog 1 (Dab1) gene. The mutant mouse is recognized by unstable gait and tremor and by early deaths around at the time of weaning. The cytoarchitectures of cerebeller and cerebral cortices and hippocampal formation of the yotari mouse are abnormal. These malformations strikingly resemble those of reeler mouse. In the present study we examined the callosal commissural (CC) neurons of yotari, reeler and normal mice with the injection of recombinant adenovirus into the frontal area 1 (Fr1) to find some possible phenotypes specific for the yotari mouse. The distribution pattern of CC neurons of the yotari was similar to that of the reeler: retrogradely labeled CC neurons were seen throughout all depths of the contralateral Fr1. However, the present statistical analysis revealed that the difference of the mean intracortical position of the CC neurons between the yotari and the reeler is significantly different (Student's t-test), suggesting that the phenotype of the yotari is clearly different from that of the reeler.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Involvement of protein kinase Cgamma isoform in morphine-induced reinforcing effects.

The present study was designed to investigate the role of protein kinase C (PKC) isoform in the morphine-induced reinforcing effect in mice. An intracerebroventricular injection of calphostin C, a specific PKC inhibitor, produced a dose-dependent reduction in the morphine-induced place preference. The protein level of PKCgamma was significantly up-regulated in membrane preparations of the limbic forebrain obtained from the morphine-conditioned mice compared to that from the saline-conditioned mice. However, the protein levels of PKCalpha, betaI, betaII and epsilon were not affected in the same preparation. By contrast, there were no changes in the protein level of all five PKC isoforms in the lower midbrain. Furthermore, we investigated the rewarding properties of morphine in mice lacking PKCgamma gene. A significant place preference was observed following treatment with morphine in wild-type mice, whereas such an effect of morphine was not found in PKCgamma knockout mice. These findings suggest that activated PKCgamma in the limbic forebrain following the treatment with morphine may be critical for the development and/or maintenance of reinforcing effects induced by morphine in mice.

Analgesics, Opioid↗

PubMed2001

Molecular cloning and dendritic localization of rat SH3P7.

SH3P7 was originally isolated by cloning SH3 domain ligand targets from a mouse embryo cDNA library. SH3P7 is an actin-binding protein implicated in antigen reception, JNK1 signalling, and Rac activation. It contains a drebrin homology sequence in its N-terminal region and a cortactin homology sequence (SH3 domain) in its C-terminal region. Both drebrin and cortactin are actin-binding proteins, and both have been suggested as possible regulators of the actin cytoskeleton in neurons. In the present study, we performed cDNA cloning of rat SH3P7, performed RT-PCR analysis, generated polyclonal antibodies against the recombinant rat SH3P7 protein, and examined the distribution of SH3P7 in the rat brain using immunohistochemistry. Sequence analysis revealed that there were at least four isoforms of the SH3P7 protein: SH3P7r1-SH3P7r4. RT-PCR analysis revealed that the predominant isoforms expressed in the brain were SH3P7r1 and SH3P7r3. The relative levels of isoform expression were similar among regions. Immunohistochemistry revealed that the most intense immunolabelling for SH3P7 was observed in the hippocampus and cerebellar cortex. Double-labelling studies with anti-SH3P7 antibody and other neuronal marker proteins revealed that SH3P7 was located primarily in dendrites, and in moderate amounts in cell bodies. Immunoreactivity was absent in the presynaptic terminals. In cultured astrocytes, SH3P7 was localized at protrusive structures of the cell periphery and in the cell body. We concluded that SH3P7 is ubiquitous in the rat brain, and occurs as several isoforms. Also, its dendritic localization suggests that SH3P7 is functionally linked to actin cytoskeleton organization in dendrites.

Amino Acid Sequence↗

PubMed2001

Construction and characterization of BAC libraries for three fish species; rainbow trout, carp and tilapia.

Bacterial artificial chromosome (BAC) libraries are important tools for genomic research. We have constructed seven genomic BAC libraries from three fish species, rainbow trout (Oncorhynchus mykiss), carp (Cyprinus carpio) and tilapia (Oreochromis niloticus). The two rainbow trout BAC libraries have average insert sizes of 58 and 110 kb. The average size of inserts in the carp BAC library is 160 kb. The average insert sizes of the four tilapia BAC libraries are 65, 105, 145 and 194 kb, respectively. These libraries represent good coverage of each genome (2-64 x coverage). The libraries can be screened by conventional colony hybridization and provide a starting point for the construction of high-density filtres or polymerase chain reaction (PCR) screening approaches. These BAC libraries will facilitate the positional cloning of quantitative trait loci (QTLs) for a variety of economically important traits in these species.

Animals↗