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Biomedical subjects

S Aoki

Publications and source records attributed to S Aoki.

At least 19 recordsLinked to original sources
PubMed1996

Cloning and expression of Xenopus HGF-like protein (HLP) and Ron/HLP receptor implicate their involvement in early neural development.

HGF-like protein (HLP), also known as macrophage stimulating protein, is a ligand for Ron receptor tyrosine kinase, a member of the c-Met/hepatocyte growth factor receptor family. We cloned a Xenopus homologue of the Ron/HLP receptor (Xron) and HLP (Xhlp) and analyzed temporal and spatial expressions. Both Xron and Xhlp mRNA were detected in Xenopus embryos at the cleavage stage, as maternally pooled RNA. Zygotic expression of Xron mRNA was seen in early embryos during midblastula and neurula (stage 22), while Xhlp was evident during midblastula and early tadpole (stage 40). Xron mRNA was localized in the most frontal region of the neural fold and peripheral regions of the neural plate, while Xhlp mRNA was seen in midline of the neural plate (notoplate) and the most frontal regions of the neural fold in early neurula. Thus, functional coupling between Ron receptor tyrosine kinase and HLP may have an important role in development of embryonic neural tissue in Xenopus laevis.

Amino Acid Sequence↗
PubMed1996

Monoclonal antibody against the fusion junction of a deletion-mutant epidermal growth factor receptor.

A mouse monoclonal antibody (IgG2b), 3C10, was produced against the truncated epidermal growth factor receptor (EGFR), encoded by the (type III) in-frame deletion mutation of 801 nucleotides of EGFR affecting the external domain, known to be expressed in some human glioblastoma. As this mutation newly generates a glycine residue at the fusion point, a 14 amino acid peptide around the fusion junction including this glycine was chemically synthesised and used for immunisation of (B6 x DBA/2) F1 mice. Flow cytometric analysis showed 3C10 antibody staining of a mouse NIH/3T3 transfectant (ERM5) with the type III EGFR deletion-mutant gene, but not one with wild-type EGFR. The antibody immunoprecipitated the truncated EGFR protein with a molecular mass of approximately 140 kDa from ERM5 cells. Immunostaining of glioblastomas revealed binding in the case with the type III EGFR mutation, the five other specimens without the mutation being negative despite overexpression of EGFR in some cases.

3T3 Cells↗
PubMed1996

Epiduroscopic changes in patients undergoing single and repeated epidural injections.

Using a superfine fiberscope with an outer diameter of 0.75 mm, the effect of repeated injections through a single epidural catheter on the epidural space was examined in 18 patients. The subjects were divided into a control group of 10 patients who had not previously received epidural anesthesia (EA) and an EA group of 8 patients who had received repeated EA with 4-6 mL 0.25% bupivacaine through an epidural catheter, two to three times per day for 7-14 days. The epidural space was observed through a fiberscope passed through a 17-gauge Tuohy needle. The epidural space was occupied by large masses of fat, and the blood vessels and connective tissue were confirmed. Adverse reactions in the epidural tissue, such as hemorrhage or congestion with engorgement, were observed in four patients in the EA group. Five patients in the EA group experienced pain when the fiberscope was inserted into the epidural space. These investigations show that continuous EA might be followed by a high incidence of nonspecific epidural changes. Superfine fiberscope may be useful in the detection or diagnosis of local epidural reaction.

Adult↗
PubMed1996

Role of enteric bacteria in the pathogenesis of rheumatoid arthritis: evidence for antibodies to enterobacterial common antigens in rheumatoid sera and synovial fluids.

OBJECTIVE: To study antibodies to Escherichia coli O:14, which expresses large amounts of enterobacterial common antigen (ECA), and their corresponding antigen molecules in serum and synovial fluid samples from patients with rheumatoid arthritis (RA). METHODS: Enzyme linked immunosorbent assay (ELISA) was used to measure antibodies to heat killed E coli O:14 in serum and synovial fluid samples from patients with RA and control subjects including healthy donors and patients with osteoarthritis. ELISA was also used to perform absorption analyses of antibodies to E coli O:14 with several enteric bacteria and their lipopolysaccharide (LPS). In addition, antigenic molecules reacting with E coli O:14 antibodies from patients with RA were examined using immunoblot analysis and N-terminal amino acid analysis. RESULTS: Compared with control subjects, patients with RA showed significantly increased titres of antibodies against heat killed E coli O:14 in 33 of 83 serum samples (39.8%) and 38 of 58 joint fluid samples (65.5%). Absorption analyses with enteric bacteria and their LPS resulted in the reduction of antibody titres to heat killed E coli O:14 in serum and synovial fluid samples from the RA patients. In addition, immunoblot analysis of the samples from RA patients revealed not only a ladder-like banding pattern equivalent to ECA associated with LPS, but also two clear bands of bacterial outer membrane proteins of 35 kDa (Omp A) and 38 kDa (Omp C), having amino acid sequence homology with those of other Enterobacteriaceae. CONCLUSION: These results suggest that some patients with RA are sensitised to antigens common to Enterobacteriaceae, and this may prove relevant to the future development of immunotherapy for RA. Furthermore, this sensitisation to antigens found commonly in Enterobacteriaceae may have a key role in the pathogenesis of human RA similar to that described previously in our animal model.

Adult↗
PubMed1996

Marine natural products. XXXVI. Biologically active polyacetylenes, adociacetylenes A, B, C, and D, from an Okinawan Marine sponge of Adocia sp.

Adociacetylenes A (1), B (2), C (3), and D (4) were isolated as new polyacetylenes from an Okinawan marine sponge of Adocia sp. Their chemical structures have been elucidated on the bases of their chemical and physicochemical properties. Adociacetylenes A (1), C (3), and D (4) exhibited inhibitory activity in the in vitro endothelial cell-neutrophil leukocyte adhesion assay.

Acetylene↗
PubMed1996

Induction therapy with all-trans retinoic acid for acute promyelocytic leukemia: a clinical study of 10 cases, including a fatal [correction of fetal] case with thromboembolism.

Ten patients with acute promyelocytic leukemia (APL) were treated with all-trans retinoic acid (ATRA). Eight of 10 patients achieved complete remission (CR), and among the 8 newly diagnosed cases, 7 achieved CR. Five of 8 CR cases remained in CR after 8 to 30 months. Except for hypotension and a large gastric ulcer resulting from hyperhistaminemia, the adverse effects of ATRA were generally mild. Severe thrombotic tendency occurred in a patient treated with ATRA combined with tranexamic acid. Intensive chemotherapy consisting of daunorubicin (DNR) and other agents was scheduled for the patients who achieved CR with ATRA.

Adult↗
PubMed1996

[Interstitial pneumonia associated with mixed connective tissue disease--marked improvement with azathioprine].

A 55-year-old man who complained dyspnea on exertion was given a diagnosis of interstitial pneumonia associated with mixed connective tissue disease, based on symptoms and on physical and laboratory findings. Soon afterward, he experienced an acute exacerbation of the interstitial pneumonia. He was given three courses of steroid pulse therapy and cyclophosphamide, but his condition worsened. After administration of azathioprine in addition to corticosteroids, his respiratory status improved. The dose of corticosteroids was tapered and the patient has been free of disease for two years. Pulmonary involvement in mixed connective tissue disease has been considered to be relatively benign and easily treated with corticosteroids. Recently, however, many cases of corticosteroid-resistant disease with poor outcome have been reported. Azathioprine was very effective against the interstitial pneumonia in this case, but general conclusions about the most effective type of immunosuppressive agent and the timing of its administration must await the results of further study.

Azathioprine↗
PubMed1995

Expression of the hepatocyte growth factor gene during chick limb development.

It has been shown that mirror-image duplications of the zeugopodia and digits are formed when MRC-5 fibroblasts producing hepatocyte growth factor (HGF) are applied to the anterior region of the chick limb bud (Yonei et al. [1993] Dev. Biol. 160:246-253). To evaluate the role of HGF in limb development, we observed the expression pattern of the HGF gene using in situ hybridization. The HGF gene was expressed in the mesoderm of the limb bud and in the central core region of mandibular arch and maxillary processes at stages 17 to 24. When both wing and leg buds begin to extend distally, the HGF gene is expressed in the mesenchymal cells, but not in the ectodermal cells and somites. Concomitant with establishment of the apical ectodermal ridge, distal mesenchymal cells of the limb bud express the HGF gene intensely with a gradient higher in the distal region. The HGF expression is later confined to the ventral and subapical mesenchyme of the limb bud, although no signal is detectable in the apical and non-ridge ectoderm. However, signal for the c-met proto-oncogene encoding the HGF receptor is not detectable in the limb bud at stages 17 to 24. These results suggest that HGF produced in the limb mesoderm may be involved in initial induction and maintenance of the apical ectoderm during limb development.

Animals↗
PubMed1995

Tissue and subcellular distribution of glucokinase in rat liver and their changes during fasting-refeeding.

The distribution of glucokinase in rat liver under both normal feeding and fasting-refeeding conditions was investigated immunohistochemically. Under normal feeding conditions, glucokinase immunoreactivity was observed in both nuclei and cytoplasm of parenchymal cells. The nuclei were stained intensely and evenly, whereas the cytoplasm showed weak immunoreactivity of different degrees of staining intensity depending on the location of the cells. The cytoplasm of perivenous hepatocytes was stained more intensely, though not so much more, than that of periportal hepatocytes. The cytoplasm of hepatocytes surrounding the terminal hepatic venule (THV), of hepatocytes surrounding the portal triad, and of some other hepatocytes showed a stronger immunoreactivity than that of residual hepatocytes. The nuclear immunoreactivity in hepatocytes surrounding the portal triad and in some other hepatocytes was weak or absent, and positive immunoreactivity was detected at the plasma membrane of some of these cells. After 72 h of fasting, glucokinase immunoreactivity was markedly decreased in all hepatocytes. After the start of refeeding, the cytoplasmic immunoreactivity began to increase first in the parenchymal cells surrounding the THV and extended to those in the intermediate zone followed by those in the periportal zone. In contrast, the increase in nuclear immunoreactivity started in hepatocytes situated in the intermediate zone adjacent to the perivenous zone and then extended to those in the perivenous zone followed by those in the periportal zone. Hepatocytes surrounding either THV or portal triad showed a distinctive change in immunoreactivity during the refeeding period. After 10 h of refeeding, strong immunoreactivity was observed in both the cytoplasm and the nuclei of all hepatocytes, and appreciable glucokinase immunoreactivity was detected at the plasma membrane of some hepatocytes. These findings are discussed from the standpoint of a functional role of glucokinase in hepatic glucose metabolism.

Animals↗
PubMed1995

Whole body X-ray irradiation to mice decreases ascorbic acid concentration in bone marrow: comparison between ascorbic acid and vitamin E.

The change in the ascorbic acid concentration in the bone marrow after whole body X-ray irradiation was compared with that in the vitamin E concentration. The ascorbic acid concentration in the bone marrow significantly decreased by 30% 1 h after exposure to 3 Gy of X-rays, whereas the vitamin E concentration in the bone marrow was significantly decreased 5 h after exposure, when the level of ascorbic acid was less than 10% of that in the control. At 24 h after exposure, the ascorbic acid concentration in the bone marrow was significantly decreased by 80% after exposure to 0.5 Gy, whereas the vitamin E concentration was significantly decreased after exposure to 1 Gy or more. In the bone marrow, the decrease in the ascorbic acid concentration was accompanied by a marked increase in the concentration of dehydroascorbic acid, an oxidized form of ascorbic acid. X-ray irradiation did not decrease either the ascorbic acid or vitamin E concentration in the serum or intestine. These findings suggest that the bone marrow is more highly susceptible to oxidative damage by radiation and that ascorbic acid plays an important defense role against it. On Day 8 after irradiation, the decreases in the vitamin E and ascorbic acid concentrations in the bone marrow showed recovery after exposure to 3 Gy, but not after the exposure to 6 Gy.

Animals↗
PubMed1995

Contribution of parenchymal and non-parenchymal liver cells to the clearance of hepatocyte growth factor from the circulation in rats.

PURPOSE: The distribution of 125I-hepatocyte growth factor (HGF) to either liver parenchymal cells (PC) or non-parenchymal cells (NPC) was investigated in rats. METHODS: After injection of a trace amount of 125I-HGF, the distribution of radioactivity determined by microautoradiography closely resembled that of 125I-epidermal growth factor which distributes mainly to PC. RESULTS: The uptake clearance of 125I-HGF estimated by determining the radioactivity of isolated liver cells was three times higher for PC than for NPC. This suggests that HGF distributes mainly to PC at relatively low doses. On the other hand, the uptake clearance by PC fell on coadministering an excess (80 micrograms/kg) of unlabeled HGF, while no change was observed for NPC, indicating that a saturable process for the hepatic handling of HGF exists only in PC where the HGF receptor is expressed. CONCLUSIONS: At such a dose the uptake clearance was comparable for both PC and NPC showing that HGF distributes to both cell types although NPC have few HGF receptors. Since the distribution to NPC was relatively non-specific and heparin-sensitive, it may be that heparin-like substances, which are believed to exist on PC and/or the extracellular matrix, also exist on NPC.

Animals↗
PubMed1995

Serological studies of the antigenic similarity between typhus group rickettsiae and Weil-Felix test antigens.

The sera from two patients with murine typhus reacted with whole cells of Rickettsia prowazekii, R. typhi, and Proteus vulgaris OX19, and with lipopolysaccharides (LPS) from the spotted fever group rickettsia strain TT-118 and P. vulgaris OX19 in the enzyme-linked immunosorbent assay. Sera from these patients reacted with ladder-like bands of LPS from R. prowazekii and R. typhi in the immunoblot, whereas the reactivity of these sera with LPS from P. vulgaris OX19 differed from each other. These results indicate that LPS from the typhus group rickettsiae and P. vulgaris OX19 contain similar epitopes.

Antibodies, Bacterial↗
PubMed1995

Cerebrospinal fluid levels of S-100b protein and neuron-specific enolase in chronic inflammatory demyelinating polyneuropathy.

We measured the cerebrospinal fluid (CSF) concentrations of S-100b protein (S-100b) and neuron-specific enolase (NSE) using enzyme immunoassay methods in 15 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), other three patients with chronic neuropathy with demyelination, eight patients with various axonal neuropathies (AN), and 46 controls, to investigate the clinical usefulness of the determination of these two specific proteins in these neuropathies. S-100b levels were elevated (> the mean +/- 2 SD levels of controls) in the majority of patients with clinically progressing CIDP (9/11), but not in the patients with AN (0/8). In parallel with the clinical improvement, S-100b levels were normalized in patients with CIDP (10/10), though total protein levels in the CSF still remained high in some of these patients (5/10). Elevation of NSE levels were seldom seen in clinically worsening patients with CIDP (1/11) or AN (1/8). Thus our results indicated that the level of S-100b in the CSF may be useful to assess the activity of actual disease process in CIDP.

Adolescent↗
PubMed1995

Circadian expression of the dnaK gene in the cyanobacterium Synechocystis sp. strain PCC 6803.

The expression of the dnaK gene in the cyanobacterium Synechocystis sp. strain PCC 6803 was continuously monitored as bioluminescence by an automated monitoring system, using the bacterial luciferase genes (luxAB) of Vibrio harveyi as a reporter of promoter activity. A dnaK-reporting bioluminescent Synechocystis strain was constructed by fusing a promoterless segment of the luxAB gene set downstream of the promoter region of the Synechocystis dnaK gene and introduction of this gene fusion into a BglII site downstream of the ndhB gene in the Synechocystis chromosome. Bioluminescence from this strain was continuously monitored and oscillated with a period of about 22 h for at least 5 days in continuous light. The phase of the rhythm was reset by the timing of the 12-h dark period administered prior to the continuous light. The period of the rhythm was temperature compensated between 25 and 35 degrees C. Thus, the bioluminescence rhythm satisfied the three criteria of circadian rhythms. Furthermore, the abundance of dnaK mRNA also oscillated with a period of about 1 day for at least 2 days in continuous light conditions, indicating circadian control of dnaK gene expression in Synechocystis sp. strain PCC 6803.

Base Sequence↗
PubMed1995

Enhancement of the intracranial arterial wall at MR imaging: relationship to cerebral atherosclerosis.

PURPOSE: To investigate the relationship between intracranial arterial wall enhancement and atherosclerosis. MATERIALS AND METHODS: Intracranial vertebral arteries of 30 patients and carotid arteries of 62 patients were studied with spin-echo magnetic resonance imaging with contrast enhancement and spatial presaturation. Arterial wall enhancement was graded as follows: stage 1, no substantial enhancement; stage 2, faint or thin area of enhancement; stage 3, definite and thick area of enhancement. RESULTS: In vertebral arteries, stage 3 enhancement was seen in 11 patients (mean age, 73.7 years) and stage 1 in eight (mean age, 56.4 years). In carotid arteries, stage 3 enhancement was seen in 13 patients (mean age, 71.0 years) and stage 1 in 21 patients (mean age, 39.0 years). In both arteries, stage was well correlated with age (P < .05). CONCLUSION: Arterial wall enhancement is related to aging and is probably due to neovascularity in association with atherosclerotic plaques. This finding may permit assessment of intracranial atherosclerosis and other vascular diseases.

Adult↗