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Biomedical subjects

S Aoki

Publications and source records attributed to S Aoki.

At least 235 records · Page 13Linked to original sources
PubMed1997

[Sero-negative tsutsugamushi disease (scrub typhus) diagnosed by polymerase chain reaction].

We report a case of sero-negative tsutsugamushi disease diagnosed by polymerase chain reaction (PCR). A 54-year-old man who worked in Nagano prefecture presented with flu-like symptoms that did not respond to cephalosporin therapy. On admission to another hospital, chest roentgenography revealed abnormal shadows; liver dysfunction was also present. Despite therapy, the patient's condition gradually worsened and he was transferred to our intensive care unit. Erythema on all extremities and scabs on the right medial femoral region and the dorsum of the left foot suggested a diagnosis of tsutsugamushi disease. We administered minocycline and gave percutaneous cardiopulmonary support for adult respiratory distress syndrome. Despite all efforts, the patient died. Although serologic tests were not positive, Karp strains of R. tsutsugamuschi were identified on PCR amplification. Autopsy revealed evidence of acute hemorrhagic pancreatitis, which has not been reported previously in tsutsugamushi disease. We conclude that PCR techniques may be useful in confirming a diagnosis of early tsutsugamushi disease.

DNA, Bacterial↗
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

Influence of fructose on Candida albicans germ tube production.

The influence of different fructose concentrations (5, 3, 1 and 0 g/l) was tested on Germ Tube (GT) production by Candida albicans strain AS3P, using a Minimal Synthetic Medium (MSM) without (NH4)2SO4. The results obtained showed good GT production in the presence of all the different fructose concentrations and in the absence of any nitrogen source. The greatest GT production was obtained with 3 g/l of fructose vs 1 g/l of glucose, after 4 hr of incubation. On the other hand fructose consumption was lower than that of glucose at all concentrations over the 4 hour period. The data obtained may suggest that fructose is metabolized in a different way from glucose for GT production by C. albicans.

Candida albicans↗
PubMed1996

A long-surviving patient with recurrences of hepatic alveolar echinococcosis after traumatic intra-abdominal rupture.

Alveolar echinococcosis of the liver (AEL) takes a progressive and malignant course. Intra-abdominal dissemination of the parasite has a miserable outcome. Complete resection of the lesion is indispensable for the curative treatment of AEL. We experienced an extremely rare case of intra-abdominal rupture of AEL. The patient had repeated recurrences of AEL following the traumatic rupture of the lesion. After repeated resections of the lesions and appropriate medication, the patient is still alive more than 25 years since the initial onset of the disease. AEL differs from unilocular echinococcosis in terms of biological behavior. We compare the pathophysiology of the two conditions.

Adult↗
PubMed1996

A vitamin-free minimal synthetic medium for Cryptococcus neoformans.

The use of a simple synthetic medium is essential for study on the growth and physiology of Cryptococcus neoformans. In the present study, a minimal synthetic liquid medium (MSM) was tested for the growth of 23 C. neoformans strains. This medium contained a low concentration of glucose, ammonium sulphate and inorganic salts with a pH value of 4.5, but no amino acids or vitamins. The strains were starved for 4 days to eliminate nutrients which might have been carried over from their pre-culture medium. Then, they were inoculated in the MSM as an initial OD of 0.020 at 550 nm and incubated at 37 degrees C for 20 days. Cell growth was generally monitored daily by measuring the absorbance at 550 nm. The medium supported the growth of the strains tested and gave an average final OD of 0.500. The results obtained indicate that C. neoformans may be autotrophic with respect to vitamins and in particular to thiamine. The MSM medium is easy to prepare and store. It is highly reproducible and useful for studies on the growth and physiology of C. neoformans.

Cryptococcus neoformans↗
PubMed1996

Glucose influence on germ tube production in Candida albicans.

The influence of different glucose concentrations was tested in minimal synthetic medium on Candida albicans strain. After 18 hours of starvation, germ-tube (GT) production, amount of consumed glucose, oxygen and the pH of the medium were checked every hour from the beginning through the end of the experiment. Optimal GT production was obtained with 1 g/l of glucose. At this concentration the greatest glucose and oxygen consumption were also noted. No pH variations in the medium were observed in all of the glucose concentrations used. At 3 and 5 g/l glucose concentrations a lower GT production were obtained. The Crab-tree effect might interfere with GT production when glucose concentration is higher than 1 g/l. This data may support the hypothesis that GT production is strictly glucose dependent.

Ammonium Sulfate↗
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

Molecular cloning of the Xenopus c-met/hepatocyte growth factor receptor and its regional expression during early development.

Hepatocyte growth factor (HGF), a ligand for c-Met receptor tyrosine kinase, regulates the cell growth, migration and morphogenesis of a wide variety of cells, and plays important roles in organogenesis in embryos as well as regeneration of organs. HGF is structurally conserved in Xenopus laevis, and the Xenopus HGF gene is expressed in neurula and tailbud embryos. In the present work, we cloned complementary DNA for the Xenopus Met/ HGF receptor and analyzed its expression during embryogenesis. The open reading frame of Xenopus c-met is 4,125 base pairs long and encodes a putative polypeptide of 1,375 amino acids. The deduced amino acid sequences of the Xenopus and human Met proteins are 63% identical, the tyrosine kinase domains in the intracellular regions showing particular homology, over 90% identity in the amino acid sequences between Xenopus and human. During Xenopus embryogenesis, c-met mRNA was expressed at a high level from the gastrula to the neurula stage, while HGF mRNA expression was seen from the early neurula stage. Whole mount in situ hybridization showed that c-met mRNA was specifically localized in the foregut region, mesenchymal tissue of the tailbud, and neural tissues in neurula embryos. Thus, c-Met is a highly conserved molecule in a wide range of species, as is its ligand, HGF. The HGF-Met system may be involved in early multiple organogenesis in Xenopus embryos.

Amino Acid Sequence↗
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

Fetal ophthalmic artery blood flow velocity waveforms.

OBJECTIVE: To evaluate alterations in vascular impedance of the fetal ophthalmic artery (OA) with advancing gestation. STUDY DESIGN: Color Doppler flow imaging and pulsed Doppler ultrasonographic assessment were performed on 28 normal fetuses, at gestational ages ranging from 21 to 40 weeks. The pulsatility index (PI) was calculated for the OA and the middle cerebral artery (MCA). Optimal models for these PI values were determined by regression analysis. A normal range of PI values for both arteries was generated. RESULTS: In the OA, the model showed a parabolic pattern during pregnancy, as was the case for MCA. The predicted PI values for the OA were always lower than those for the MCA. CONCLUSION: Our study is the first to demonstrate alterations in regional vascular impedance of the fetal OA with advancing gestation. These data provide a foundation for the evaluation of fetal ocular circulation in normal and abnormal pregnancies.

Blood Flow Velocity↗