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Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 199 records · Page 11Linked to original sources
PubMed2001

Super high-dose intraarterial cisplatin infusion under percutaneous pelvic perfusion with extracorporeal chemofiltration for advanced uterine cervical carcinoma: I. Analysis for pharmacokinetics, tumor response, and toxicity of platinum.

The present study was designed to elucidate the clinical feasibility of a new intraarterial infusion system with an extracorporeal charcoal chemofiltration circuit, which is expected to achieve a super high-dose cisplatin pelvic perfusion with a limited systemic exposure to platinum. After inferior vena cava isolation was percutaneously achieved by balloon catheter technique, cisplatin (140-240 mg/m2) was administered by selective intrauterine arterial infusion, with inferior and superior gluteal arterial embolization. The platinum-containing blood was pumped through an extracorporeal charcoal chemofiltration circuit. Pharmacokinetics, tumor response, and toxicity of platinum under this system were studied in 14 patients with locally advanced uterine cervical carcinoma. Extracorporeal charcoal filters significantly (p < 0.05) reduced the prefilter area under concentration-time curve of plasma-free platinum by 86.7 +/- 5.2% at postfilter site and 76.3 +/- 6.6% at peripheral circulation, respectively. Although all adverse effects were mild under this system, tumor response and tissue platinum concentrations were augmented dose dependently with the administration of cisplatin. The extracorporeal chemofiltration system achieved a super high-dose cisplatin pelvic perfusion with the minimal adverse effects, allowing further cisplatin dose escalation with further augmented tumor response. This will contribute to the reduction in the extent of disease of locally advanced uterine cervical carcinoma.

Adenocarcinoma↗
PubMed2001

Super high-dose intraarterial cisplatin infusion under percutaneous pelvic perfusion with extracorporeal chemofiltration for advanced uterine cervical carcinoma: II. Its impact on clinical response and subsequent surgery.

The present pilot study was conducted to investigate the clinical efficacy of super high-dose intraarterial cisplatin infusion with percutaneous pelvic perfusion under extracorporeal chemofiltration (PPPEC) for locally advanced uterine cervical carcinoma. Cisplatin (140-240 mg/m2) was infused in uterine arteries in a neoadjuvant setting in 20 patients under the PPPEC system twice during a 2-week interval. Fourteen of 17 patients in whom reduction of the disease (tumor downstaging) was confirmed underwent radical surgery. Despite the tumor downstaging, the remaining three patients had poor PS and the other three showed insufficient stage regression. Clinical responses, histologic responses, and surgical review were studied. The rate of overall tumor response (complete response plus partial response), tumor downstaging, overall histologic response, and radical surgery performance after the second course of PPPEC were 95.0%, 85.0%, 95.0%, and 70.0%, respectively. Curative surgery, defined as negative carcinoma cells in surgical margins, was achieved in 85.7% of the cases, whereas the rate of complete surgery defined as negative carcinoma cells both in surgical margins and regional lymph nodes was 42.9%. With 42 months of median follow-up time, 3 of the 14 surgical patients died of the original disease, and the remaining 9 patients are in recurrence-free survival, whereas 2 patients are alive with disease. PPPEC achieved a high frequency of rapid tumor downstaging of locally advanced uterine cervical carcinoma without severe adverse effects and resulted in the favorable performance of the subsequent radical surgery and prognosis.

Adenocarcinoma↗
PubMed2001

Brassinosteroid levels increase drastically prior to morphogenesis of tracheary elements.

As the first step toward understanding the involvement of endogenous brassinosteroids (BRs) in cytodifferentiation, we analyzed biosynthetic activities of BRs in zinnia (Zinnia elegans L. cv Canary Bird) cells differentiating into tracheary elements. The results of feeding experiments suggested that both the early and late C6-oxidation pathways occur during tracheary element differentiation. Gas chromatography-mass spectrometry analysis revealed that five BRs, castasterone, typhasterol, 6-deoxocastasterone, 6-deoxotyphasterol, and 6-deoxoteasterone, actually existed in cultured zinnia cells and culture medium. Quantification of endogenous BRs in each stage of tracheary element differentiation by gas chromatography-mass spectrometry exhibited that they increased dramatically prior to the morphogenesis, which was consistent with the idea that BRs are necessary for the initiation of the final stage of tracheary element differentiation. Moreover, the proportion of each BR in culture medium was quite different from that in cells, suggesting that specific BRs are selectively secreted into medium and may function outside the cells.

Asteraceae↗
PubMed2001

Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD.

In the chloroplast psbD light-responsive promoter (LRP), a highly conserved sequence exists upstream from the bacterial -10/-35 elements. Multiple sequence-specific DNA binding proteins are predicted to bind to the conserved sequence as transcription factors. Using yeast one-hybrid screening of an Arabidopsis cDNA library, a possible DNA binding protein of the psbD LRP upstream sequence was identified. The protein, designated PTF1, is a novel protein of 355 amino acids (estimated molecular weight of 39.6) that contains a basic helix-loop-helix DNA binding motif in the predicted N-terminal region of the mature protein. Transient expression assay of PTF1-GFP fusion protein showed that PTF1 was localized in chloroplasts. Using the modified DNA sequence in the one-hybrid system, the ACC repeat was shown to be essential for PTF1 binding. The rate of psbD LRP mRNA accumulation was reduced in a T-DNA-inserted Arabidopsis ptf1 mutant. Compared with wild-type plants, the mutant had pale green cotyledons and its growth was inhibited under short-day conditions. These results suggest that PTF1 is a trans-acting factor of the psbD LRP.

Amino Acid Sequence↗
PubMed2001

Brassinosteroid-6-oxidases from Arabidopsis and tomato catalyze multiple C-6 oxidations in brassinosteroid biosynthesis.

Brassinosteroids (BRs) are steroidal plant hormones that are essential for growth and development. It has been proposed that BRs are synthesized via two parallel pathways, the early and late C-6 oxidation pathways according to the C-6 oxidation status. The tomato (Lycopersicon esculentum) Dwarf gene encodes a cytochrome P450 that has been shown to catalyze the C-6 oxidation of 6-deoxocastasterone to castasterone. We isolated an Arabidopsis ortholog (AtBR6ox gene) of the tomato Dwarf gene. The encoded polypeptide has characteristics of P450s and is classified into the CYP85 family. The AtBR6ox and tomato Dwarf gene were expressed in yeast and the ability of the transformed yeast cells to metabolize 6-deoxo-BRs was tested. Metabolites were analyzed by gas chromatography-mass spectrometry. Both enzymes catalyze multiple steps in BR biosynthesis: 6-deoxoteasterone to teasterone, 3-dehydro-6-deoxoteasterone to 3-dehydroteasterone, 6-deoxotyphasterol to typhasterol, and 6-deoxocastasterone to castasterone. Our results indicate that the AtBR6ox gene and the tomato Dwarf gene encode steroid-6-oxidases and that these enzymes have a broad substrate specificity. This suggests that the BR biosynthetic pathway consists of a metabolic grid rather than two separate parallel pathways.

Amino Acid Sequence↗
PubMed2001

Fate of Legionella pneumophila in macrophages of C57BL/6 chronic granulomatous disease mice.

We compared the intracellular survival and growth of Legionella pneumophila Philadelphia-1 in peritoneal macrophages obtained from A/J, C57BL/6, and X-linked chronic granulomatous disease (CGD) mice produced from C57BL/6 strain. The initial killing was observed in A/J and C57BL/6 macrophages at 2, 4 and 6 hr after in vitro phagocytosis, but not in the CGD macrophages. Thereafter, there was a 10-fold increase of CFU in A/J macrophages. The bacteria, however, did not proliferate in C57BL/6 and CGD macrophages at 24 or 48 hr after in vitro phagocytosis. These results suggest that effector molecules for the initial killing are a superoxide anion and its metabolites, and Lgn1 gene product inhibits the intracellular growth of L. pneumophila independently of NADPH oxidase.

Animals↗
PubMed2001

Morphological variety of intracellular microcolonies of Legionella species in Vero cells.

Intracellular microcolonies of six Legionella species growing in Vero cells showed distinctly varied morphologies. The varieties were observed by light microscopy of Gimenez-stained, Legionella-infected Vero cells and by electron microscopy (EM). Legionella pneumophila Philadelphia-1 formed needle-shaped crystal-like microcolonies. Legionella bozemanii WIGA formed microcolonies like wool balls containing filamentous cells. In EM, these organisms proliferated in endosomes, which were adjacent to swollen rough endoplasmic reticula. Legionella oakridgensis OR-10 showed serpentine chains. Many mitochondria were observed around the microcolonies. Legionella jordanis BL-540 formed spherical moss-like microcolonies which were or were not surrounded by endoplasmic membranes. Legionella feeleii WO-44C spread throughout the cytoplasm without making clusters. Legionella dumoffii Tex-KL made big clusters that spread in the cytoplasm, a portion of which was outside the endosome membranes. These different morphologies imply diversity in modes of intracellular multiplication of Legionella spp.

Animals↗
PubMed2001

Purification and characterization of the recombinant Thermus sp. strain T2 alpha-galactosidase expressed in Escherichia coli.

The nucleotide sequence of the Thermus sp. strain T2 DNA coding for a thermostable alpha-galactosidase was determined. The deduced amino acid sequence of the enzyme predicts a polypeptide of 474 amino acids (M(r), 53,514). The observed homology between the deduced amino acid sequences of the enzyme and alpha-galactosidase from Thermus brockianus was over 70%. Thermus sp. strain T2 alpha-galactosidase was expressed in its active form in Escherichia coli and purified. Native polyacrylamide gel electrophoresis and gel filtration chromatography data suggest that the enzyme is octameric. The enzyme was most active at 75 degrees C for p-nitrophenyl-alpha-D-galactopyranoside hydrolysis, and it retained 50% of its initial activity after 1 h of incubation at 70 degrees C. The enzyme was extremely stable over a broad range of pH (pH 6 to 13) after treatment at 40 degrees C for 1 h. The enzyme acted on the terminal alpha-galactosyl residue, not on the side chain residue, of the galactomanno-oligosaccharides as well as those of yeasts and Mortierella vinacea alpha-galactosidase I. The enzyme has only one Cys residue in the molecule. para-Chloromercuribenzoic acid completely inhibited the enzyme but did not affect the mutant enzyme which contained Ala instead of Cys, indicating that this Cys residue is not responsible for its catalytic function.

Amino Acid Sequence↗
PubMed2001

Type 1 fimbriation and its phase switching in diarrheagenic Escherichia coli strains.

Type 1 fimbriae can be expressed by most Escherichia coli strains and mediate mannose-sensitive (MS) adherence to mammalian epithelial cells. However, the role of type 1 fimbriae in enteric pathogenesis has been unclear. Expression of type 1 fimbriae in E. coli is phase variable and is associated with the inversion of a short DNA element (fim switch). Forty-six strains of diarrheagenic E. coli were examined for the expression of type 1 fimbriae. Only four of these strains were originally type 1 fimbriated. Seventeen strains, originally nonfimbriated, expressed type 1 fimbriae in association with off-to-on inversion of the fim switch, after serial passages in static culture. The switching frequencies of these strains, from fimbriate to nonfimbriate, were greater than that of the laboratory strain E. coli K-12. None of the 16 strains of serovar O157:H7 or O157:H(-) expressed type 1 fimbriae after serial passages in static culture. The nucleotide sequence analysis of the fim switch region revealed that all of the O157:H7 and O157:H(-) strains had a 16-bp deletion in the invertible element, and the fim switch was locked in the "off" orientation. The results suggest that expression of type 1 fimbriae may be regulated differently in different E. coli pathogens causing enteric infections.

Bacterial Adhesion↗
PubMed2001

Endoscopic mucosal resection for treatment of early gastric cancer.

BACKGROUND: In Japan, endoscopic mucosal resection (EMR) is accepted as a treatment option for cases of early gastric cancer (EGC) where the probability of lymph node metastasis is low. The results of EMR for EGC at the National Cancer Center Hospital, Tokyo, over a 11 year period are presented. METHODS: EMR was applied to patients with early cancers up to 30 mm in diameter that were of a well or moderately histologically differentiated type, and were superficially elevated and/or depressed (types I, IIa, and IIc) but without ulceration or definite signs of submucosal invasion. The resected specimens were carefully examined by serial sections at 2 mm intervals, and if histopathology revealed submucosal invasion and/or vessel involvement or if the resection margin was not clear, surgery was recommended. RESULTS: Four hundred and seventy nine cancers in 445 patients were treated by EMR from 1987 to 1998 but submucosal invasion was found on subsequent pathological examination in 74 tumours. Sixty nine percent of intramucosal cancers (278/405) were resected with a clear margin. Of 127 cancers without "complete resection", 14 underwent an additional operation and nine were treated endoscopically; the remainder had intensive follow up. Local recurrence in the stomach occurred in 17 lesions followed conservatively, in one lesion treated endoscopically, and in five lesions with complete resection. All tumours were diagnosed by follow up endoscopy and subsequently treated by surgery. There were no gastric cancer related deaths during a median follow up period of 38 months (3-120 months). Bleeding and perforation (5%) were two major complications of EMR but there were no treatment related deaths. CONCLUSION: In our experience, EMR allows us to perform less invasive treatment without sacrificing the possibility of cure.

Adult↗
PubMed2001

Simple techniques suitable for student use to record action potentials from the frog heart.

Demonstrating action potentials during class experiments is very educational for science students. It is not easy, however, to obtain a stable intracellular recording of action potentials from the conventionally used skeletal muscle cells, because the tip of a glass microelectrode often comes out or breaks due to muscle contraction. Here, I present a much simpler recording method using a flexible polyethylene electrode with a wide orifice (approximately 1 mm) for a bullfrog heart beating on automaticity. Extracellular recordings of action potentials (electrocardiogram) can be obtained by placing an electrode on the cardiac surface, and transmembrane potentials can be obtained by rupturing the membrane with negative pressure, i.e., whole cell configuration. Once attached to the heart by suction, the polyethylene electrode does not easily come off during contraction of the heart. Perfusion of the heart via the postcaval vein offers us opportunities for observing the effects of either changing ionic compositions of solutions or applying drugs. The techniques shown here provide a simple and convenient way to perform a variety of class experiments.

Action Potentials↗
PubMed2001

Parallel induction of nitric oxide and tetrahydrobiopterin synthesis in alveolar macrophages.

BACKGROUND: Nitric oxide (NO) and an essential cofactor for both constitutive and inducible NO synthase (NOS) activity, tetrahydrobiopterin (6R-L-erythro-1',2'-dihydroxypropyl-2-amino-4-hydroxy-5,6,7,8-tetrahydropteridine; BH4), are thought to be important modulators of function in normal and inflamed airways. However, the exact pathologic roles of NO and BH4 remain obscure. Even less is known about the effects of cytokines on alveolar macrophages. OBJECTIVE: This study was designed to determine whether NO and BH4 are induced by cytokines in mouse alveolar macrophages and to investigate whether NO synthesis is affected by changes in intracellular BH4 levels in alveolar macrophages. METHODS: We compared the induction by lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-2 (IL-2) of NO production and BH4 synthesis in alveolar macrophages. To determine whether NO synthesis is affected by changes in intracellular BH4 levels in alveolar macrophages, we used inhibitors of BH4 biosynthesis. RESULTS: Activation of alveolar macrophages induced parallel increases in NO and intracellular BH4 levels, although induction of the latter appears to be somewhat more sensitive than that of the latter to diverse cytokines. Inducible NO production in alveolar macrophages was blocked by inhibitors of BH4 biosynthesis. IL-2, an important component of the immunomodulatory system, was only a weak activator of alveolar macrophages by itself but potently synergized with IFN-gamma to stimulate the production of both NO and BH4. CONCLUSION: Our results suggest that BH4 synthesis in alveolar macrophages is a potential target for therapeutic intervention in airway inflammatory diseases, such as asthma, cystic fibrosis, and acute bronchial infections whose pathology may be mediated by overproduction of NO.

Animals↗
PubMed2001

Possible relevance of virus infection for development of analgesic idiosyncrasy.

Although it has been hypothesized that analgesic idiosyncrasy could be acquired by viral infection, there is no evidence that any virus can cause sporadic cases of aspirin-intolerant asthma. We report a case, which points to the possible relevance of herpes simplex virus (HSV) infection for development of analgesic idiosyncrasy. We examined the patient to evaluate whether analgesic idiosyncrasy might have been acquired by viral infection. Sulpyrine provocation testing was performed to confirm the patient's development of analgesic idiosyncrasy and methacholine provocation testing was performed to assess bronchial hyperresponsiveness. The titer of anti-HSV IgG antibody was measured to confirm viral infection. Sulpyrine provocation testing revealed that hypersensitivity to analgesics had appeared in this patient. In contrast, the marked improvement of her bronchial hyperresponsiveness was confirmed by a PC(20) methacholine of 0.63 mg/ml 1 week after sulpyrine provocation testing. The anti-HSV IgG antibody confirmed recent HSV infection. To the best of our knowledge, this is the first reported case of acquired analgesic idiosyncrasy following HSV infection.

Adult↗
PubMed2001

Availability of learned helplessness test as a model of depression compared to a forced swimming test in rats.

This study was designed to evaluate the antidepressant activity of various antidepressants using the learned helplessness test (LH) or the forced swimming test (FS) in rats. Repeated treatment of the tricyclic antidepressants imipramine (10 mg/kg, p.o.), clomipramine (0.625 mg/kg, p.o.), amitriptyline (10 mg/kg, p.o.) and amoxapine (20 mg/kg, p.o.) reduced the number of escape failures in the LH group, respectively. Repeated treatment of an atypical antidepressant, mianserin (2.5 and 5 mg/kg, p.o.), and one of the selective serotonin reuptake inhibitors (SSRI), fluvoxamine (1.25 mg/kg, p.o.), also reduced the number of escape failures in the LH group. In the FS, repeated treatment of imipramine (5, 10 mg/kg, p.o.), amitriptyline (5, 10 mg/kg, p.o.) and mianserin (10 mg/kg) significantly decreased the duration of immobility time. On the other hand, repeated treatment of amoxapine (5-20 mg/kg), clomipramine (0.1325-1.25 mg/kg, p.o.) and fluvoxamine (0.3125-1.25 mg/kg, p.o.) failed to decrease the duration of immobility time in the FS group. In conclusion, these results suggest that the LH group is sensitive to agents with a variety of antidepressant properties compared to the FS group in rats.

Amoxapine↗
PubMed2001

Nanosized Ni/SiO2 catalyst prepared by homogeneous precipitation in wet silica gel.

A Ni/SiO2 catalyst was prepared by homogeneous precipitation of nickel hydroxide in a sol-gel-derived wet silica gel. The preparation process consists of two successive steps: gelation of silica in the presence of nickel nitrate and urea at 50 degrees C, followed by aging at higher temperature, typically at 80 degrees C, to decompose the urea. The decomposition of urea increases the pH of the solution in the wet gel, leading to the concurrence of structural rearrangement of silica gel and deposition of nickel species. As a result, the structure of the silica changes from a ramified polymeric network into particle aggregates that entrap the nickel cations in the particles. The resulting Ni/SiO2 contains large mesopores that have high thermal stability up to 1000 degrees C and highly dispersed Ni metal particles with typical crystallite size of 4 nm even at high Ni content at 20 wt%.

Catalysis↗