Biomedical subjects

Y Fujita

Publications and source records attributed to Y Fujita.

At least 19 recordsLinked to original sources

PubMed1992

[Experimental study of indirect lymphography with iodinated starch].

Opacification of lymph nodes on CT was attempted by means of indirect lymphography with iodinated starch (IS). Sixty percent solutions of two different molecular weights of IS were prepared (5,000 mol wt and 70,000 mol wt in average). After subcutaneous injection of IS solutions to the pedal area of dogs, CT scans were performed to evaluate opacification of the popliteal lymph nodes. The lymph nodes began to be opacified from 10 min after the injection of each solution. The high molecular weight IS showed higher attenuation and longer duration of opacification than did the low molecular weight IS. Homogeneity of opacification was better with latter. The optimum molecular weight for this purpose is considered to be between 5,000 and 70,000 mol wt.

Animals↗

PubMed1992

Antiepileptic effects of CNK-602A, a novel thyrotropin-releasing hormone analog, on absence-like and tonic seizures of spontaneously epileptic rats.

The effects of CNK-602A (N-[(6-methyl-5-oxo-3-thiomorpholinyl) carbonyl]-L-histidyl-L-prolinamide), a novel thyrotropin-releasing hormone related analog, were investigated on absence-like seizure and tonic convulsion in the spontaneously epileptic rat (SER), which is a genetically defined double-mutant. When CNK-602A of 0.2-1 mg/kg was given intravenously to the animal, there were no changes in the background EEG except for an increase in low-voltage fast waves concomitant with behavioral alertness. However, CNK-602A suppressed absence-like seizure and tonic convulsion in a dose-dependent manner for over 1 h. These antiepileptic effects of CNK-602A on both seizures were antagonized by pretreatment with haloperidol (1 mg/kg, i.p.). It was found, using a brain in vivo microdialysis method, that CNK-602A at a dose of 1 mg/kg, which inhibits the seizures, increased the release of dopamine in the caudate nucleus. These results suggest that CNK-602A inhibits the seizures of SER in a similar manner to thyrotropin-releasing hormone (TRH), probably by increasing the release of dopamine in the central nervous system. In addition, the antiepileptic effects of CNK-602A were more potent and lasted longer than those of TRH.

Animals↗

PubMed1992

Neutrophil priming by granulocyte colony stimulating factor and its modulation by protein kinase inhibitors.

Upon stimulation by various ligands, freshly isolated human peripheral neutrophils (PMN) respond in a variety of ways, such as superoxide (O2-.) generation, phagocytosis enzyme release, migration etc. Chemotactic peptide formylmethionyl-leucyl-phenylalanine (FMLP) and opsonized zymosan activate neutrophils by a receptor-mediated mechanism, while phorbol myristate acetate and dioctanoylglycerol activate the cells by a mechanism involving Ca(2+)-and phospholipid-dependent protein kinase (PKC). Receptor-mediated but not PKC-mediated O2-. generation in PMN was enhanced by the priming of recombinant human granulocyte colony stimulating factor (G-CSF). FMLP-dependent luminol chemiluminescence was also enhanced by G-CSF. However, no appreciable enhancement was observed in FMLP-induced intracellular calcium ion concentration ([Ca2+]i). Enhancement of FMLP-induced generation of O2-. by G-CSF was inhibited by genistein or alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK), and was stimulated by staurosporine and 1-(5-isoquinolinesulfonyl)-3-methyl-piperazine (H-7), inhibitors of PKC. The ED50 values of genistein and ST 638 for the inhibition of the FMLP-induced O2-. generation from G-CSF were 0.5 and 5 microM, respectively. In contrast, O2-. generation by PKC activation without G-CSF priming was inhibited by stauroporine and H-7, but was stimulated by genistein and ST 638. These results suggested that the enhancing effect of G-CSF on receptor-mediated generation of the O2-. might be regulated by protein kinases, such as TK and PKC, and that the TK inhibitor selectively inhibited the G-CSF-primed receptor-mediated O2-. generation of neutrophils.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1992

[Transcatheter embolization for huge pulmonary arteriovenous fistula using metallic "spider" and spring embolus--application of hand-made metallic "spider" using partial monorail technique].

We performed transcatheter embolization in two cases with huge pulmonary arteriovenous fistula (AVF) using a metallic "spider" and spring embolus. Conventional spring embolus or detachable balloon could not be used in these cases. Metallic spider was indicated for pulmonary AVF with a feeding artery diameter of more than 16 mm to prevent embolus passing through the AVF. In the first case, we used large handmade metallic spiders of 25 mm in diameter followed by embolization by numerous spring coils. At that time, a partial monorail technique was newly devised to carry the large metallic spider into the feeding artery, otherwise the spider could not pass into a 9F catheter. After embolization, symptoms and PaO2 in arterial blood improved remarkably in both cases. In the second case, a spring coil migrated into the normal pulmonary artery, but no infarction resulted. In conclusion, the metallic spider was very useful for embolization of hugee pulmonary AVF to avoid the embolus passing through and to tangle spring coils together with it. If commercially available "spiders" are too small, ones can be made easily.

Adult↗

PubMed1992

Overproduction, purification and characterization of SecD and SecF, integral membrane components of the protein translocation machinery of Escherichia coli.

SecD and SecF proteins were overproduced by means of recombinant DNA technology. Immunoblot and amino-acid sequencing analysis revealed that the overproduced proteins are SecD and SecF. The SecD- or SecF-overproduced membrane fraction was subjected to differential solubilization. The SecD protein was then purified through ion-exchange and size-exclusion chromatographies. The SecF protein was purified through size exclusion chromatography. Proteoliposomes reconstituted from the purified SecD and SecF together with SecE and SecY were used to analyze the translocation activity. SecD and SecF did not exhibit significant effects on the translocation activity of proteoliposomes. The amounts of SecD and SecF in overproducers were determined densitometrically on a stained SDS gel and their overproduction (fold) was determined by means of immunoblot analysis. Then the number of these molecules in one normal cell were estimated. From these numbers, together with those of other Sec proteins, the number of the translocation machinery existing in one Escherichia coli cell was inferred to be around 500.

Bacterial Outer Membrane Proteins↗

PubMed1992

Isolation and partial characterization of a compound with siderophore activity from Vibrio parahaemolyticus.

A compound with siderophore activity was purified by successive column and thin layer chromatographic procedures from Dowex 1 x 8 extracts of culture supernatants of Vibrio parahaemolyticus AQ 3354. The strain synthesized the compound in culture media containing less than 2 microM added FeCl3. Hydrolysis of the compound yielded alanine, ethanolamine, citric acid and 2-ketoglutaric acid. The 1H-NMR spectrum exhibited the presence of a residue from each of these components in the intact molecule. The fast-atom bombardment mass spectrum of the methyl ester derivative indicated a prominent ion at m/z 477, probably corresponding to [M + 1] ion. Other strains of V. parahaemolyticus were also found to produce this compound when grown in an iron-limited medium.

Cell Fractionation↗

PubMed1992

[New puncture technique for TIPSS (transjugular intrahepatic portosystemic stent shunt)].

To establish a safer puncture method for TIPSS (Transjugular Intrahepatic Portosystemic Stent Shunt), we developed a new percutaneous puncture technique to penetrate portal and hepatic vein trans-hepatically under ultrasonography (US technique). Experimentally we compared this technique with conventional transjugular technique puncturing portal vein through hepatic vein using Ross needle (Ross Needle technique). Success rate is 100% in US technique and 50% in Ross needle technique. Seven complication including intraperitoneal bleeding occurred in Ross needle technique, but no complication in US technique. Conclusively, US technique is a safer and more reliable method than that using Ross needle in the puncture method for TIPSS.

Animals↗

PubMed1992

Differences in ceramic-bone interface between surface-active ceramics and resorbable ceramics: a study by scanning and transmission electron microscopy.

The interface between bioactive ceramics and bone was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The materials were apatite-wollastonite-containing glass ceramic (A-W.GC) as a representative surface-active ceramic, and calcite and beta-tricalcium phosphate (beta-TCP) as resorbable ceramics. Particles of these materials, ranging between about 100 microns and 300 microns in diameter, were implanted into rat tibiae, and specimens were prepared for observation at 8 weeks after implantation. Both SEM and TEM demonstrated that A-W.GC was bonded to bone through a thin Ca-P-rich layer consisting of fine apatite crystals apparently different from those of bone in shape, size, and orientation. Collagen fibers of the bone reached the surface of this layer, and chemical bonding between A-W.GC and the bone was speculated. Calcite and beta-TCP, on the other hand, made direct contact with the bone, and no apatite layer was present at the interface. The surfaces of the implants became rough due to degradation, and bone grew into the finest surface irregularities. However, we were unable to demonstrate any continuity of crystals between the resorbable implants and bone by high-resolution TEM. Accordingly, the bonding strength was considered to be mainly attributable to mechanical interlocking.

Animals↗

PubMed1992

Mechanism and strength of bonding between two bioactive ceramics in vivo.

A study was conducted to examine the mechanism and strength of bonding between two bioactive ceramic plates in vivo. Rectangular plates (15 mm X 10 mm X 2 mm) of Bioglass, apatite-wollastonite-containing glass ceramic (designated A-W.GC), and two types of hydroxyapatite sintered at 900 degrees C and 1200 degrees C (designated HA900 and HA1200) were prepared. Two plates of the same materials tied together with silk thread were implanted subcutaneously into rats. The force required to detach the mutually bonded bioactive ceramic plates was measured 4, 8, 12, and 24 weeks after implantation. The interface between the two bonded plates was examined by SEM-EPMA and thin-film x-ray diffraction analysis. At 24 weeks after implantation, the mutual bonding of Bioglass and A-W.GC was stronger than that of the two HA types. SEM-EPMA and thin-film x-ray diffraction analysis of the bonded area of Bioglass and A-W.GC plates showed bonding zones with apatite in the margins, and a bonding zone with calcite in the center. The greater strength of bonding of Bioglass and A-W.GC plates compared with the two types of HA plate 24 weeks after implantation is explained by the wider bonding zone provided by the calcite layer formed in the center of the plates, which is considered to have been perfused with PO4-poor body fluids resulting from PO4 consumption for apatite formation in the margins.

Animals↗

PubMed1992

YIGSR, a synthetic laminin peptide, inhibits the enhancement by cyclophosphamide of experimental lung metastasis of human fibrosarcoma cells.

Tumor cells must attach themselves to basement membranes, through which they degrade and migrate, in order to spread to distant sites. If vascular endothelial cells are damaged by pretreatment with anticancer drugs and the subendothelial basement membranes are exposed, the attachment of malignant cells to basement membranes and subsequent metastasis formation in some tissues may be enhanced. In this study, the pretreatment of endothelial cell monolayers and mice with cyclophosphamide (CPA) was respectively shown to promote the adhesion of HT1080 human fibrosarcoma cells to endothelial cell monolayers in vitro and lung colonization in vivo. YIGSR, a synthetic laminin pentapeptide, inhibited the enhancement of lung colonization by CPA when it was co-injected intravenously with tumor cells. This inhibitory effect of YIGSR may be due to a reduction in the adhesion of HT1080 cells to injured blood vessel walls since YIGSR inhibited both the adhesion of HT1080 cells to CPA-treated endothelial cell monolayers and the invasion through basement membranes in vitro.

Animals↗

PubMed1992

A case-control study of breast cancer among Japanese women: with special reference to family history and reproductive and dietary factors.

To study the effects of family history and reproductive, anthropometric, and dietary factors on the risk of breast cancer among low risk populations, we conducted a hospital-based case-control study involving 908 patients with breast cancer and their matched controls, in Japan. A positive family history of breast cancer significantly increased the risk of breast cancer (odds ratio = 1.52, 95% confidence interval: 1.14-2.03). The risk further increased with increasing number of family members affected. Obesity, single marital status, fewer births, a late childbirth, and less consumption of green-yellow vegetables and dairy products were also associated with an increased risk of breast cancer. These associations were independent in multivariate analyses. There was no increase in risk associated with consumption of high fat foods. When analyzed by menopausal status, the association with family history of breast cancer, especially in the first degree of relatives, was more evident for premenopausal breast cancer. The associations with obesity and lower consumption of dairy products were more pronounced for postmenopausal breast cancer, while those with lower parity and single marital status were stronger for premenopausal breast cancer.

Adult↗

PubMed1992

Degradation of cadmium metallothionein in vitro by lysosomal proteases.

The effects of various protease inhibitors on the degradation of cadmium metallothionein (Cd-MT) by lysosomal proteases were studied in vitro. Degradation of Cd-MT was observed after incubation with the lysosomal extracts, but not after incubation with the cytosol or heat-treated lysosomal extracts. After incubation of [35S]-Cd-MT or 109Cd-MT with lysosomal extracts, 35S and 109Cd radioactivity in the MT fraction decreased, while the low molecular weight (LM) fraction increased with time (half life; 3 hr). When EDTA was added to this incubation mixture, most of the MT was degraded within 30 min. Cd in the LM fraction, produced after the incubation of Cd-MT with the lysosomal extracts, was moved to the high molecular weight fraction by the addition of cytosol. Both leupeptin and E-64, which reduced cathepsin B (cysteine protease) activity, inhibited the degradation of Cd-MT by the lysosomal extracts. But pepstatin A, a specific inhibitor of cathepsin D, did not inhibit this degradation. E-64 inhibited degradation, as well as inhibiting cathepsin B activity, in accordance with its concentration in the incubation mixture. The incubation of Cd-MT with purified cathepsin B resulted in its degradation which was inhibited by E-64. These results suggest that Cd-MT may be broken down by the cysteine protease in lysosomes and that the released Cd bound low molecular weight fragment(s) was subsequently transferred to the high molecular weight protein in cytosol.

Animals↗

PubMed1992

Effects of mucosal metallothionein in small intestine on tissue distribution of cadmium after oral administration of cadmium compounds.

The effect of mucosal metallothionein (MT) preinduced by zinc (Zn) on tissue distribution of cadmium (Cd) after administration of Cd with several chelating agents was studied in rats. After Cd-cysteine (Cd-Cys) was incubated with intestinal Zn-MT in vitro, all the Cd dissociated from Cys and exchanged the Zn bound to MT. However, dissociation of Cd bound to EDTA (Cd-EDTA) was not observed in the incubation mixture containing intestinal Zn-MT. The concentration of Cd in intestinal mucosa reached a maximum 16 hr after oral administration of Cd-Cys. The Cd level in the intestine was higher than that in the liver and kidney and was similar to that occurring after oral administration of CdCl2. The amount of Cd distributed to the liver and kidney after Cd-EDTA administration was about 30% of the level after CdCl2 administration. Even at 15 mg Cd/kg Cd-EDTA, the Cd level in the intestinal mucosa reached a plateau after 2-4 hr, as it did in the liver and kidney. When Cd-Cys was administered po to control or to Zn-pretreated rats, it was found that Zn pretreatment increased the concentration of Cd in the kidney, as was the case after oral administration of CdCl2. This effect of Zn pretreatment was not observed after oral administration of Cd-EDTA. When Cd-MT was injected into the duodenum, the intestinal absorption of Cd was 60% of that after CdCl2 administration. After the duodenal administration of Cd-MT, at all doses, the concentration of Cd in the kidney was higher than that in the liver. These results suggest that mucosal MT in the small intestine might trap Cd absorbed from the intestinal lumen and transport it to the kidney.

Administration, Oral↗

PubMed1992

Plasma concentrations of lignocaine after obturator nerve block combined with spinal anaesthesia in patients undergoing transurethral resection procedures.

Bilateral obturator nerve block has become a widely accepted technique to avoid adductor contraction during transurethral resection of prostate or bladder tumours. However, little is known about plasma lignocaine concentrations after the block. We conducted this study to assess a safe dose of lignocaine for injection in obturator nerve block. Bilateral obturator nerve block was performed with the aid of a peripheral nerve stimulator in 12 patients after spinal anaesthesia. In group I (n = 6), patients received 2% lignocaine 10 ml (200 mg) for the block; those in group II (n = 6) received 2% lignocaine 15 ml (300 mg). The block was satisfactory and no single adductor contraction was observed in either group during surgery. The peak plasma concentrations of lignocaine were 2.28 (SD 0.29) micrograms ml-1 and 3.75 (0.79) micrograms ml-1 in groups I and II, respectively. The greatest plasma concentration was 5.07 micrograms ml-1 in a patient of group II. There were no symptoms suggesting systemic toxicity. We conclude that bilateral obturator nerve block may be performed safely and effectively with 2% lignocaine 10 ml with the aid of a peripheral nerve stimulator in patients undergoing transurethral resection procedures with spinal anaesthesia.

Aged↗

PubMed1992

Ecologic study of lung cancer risk factors in the U.S. and Japan, with special reference to smoking and diet.

Lung cancer mortality rates among United States and Japanese males were compared and related to smoking and dietary data. Mortality rates increased from 1950 to 1985 in both countries, but the absolute values are consistently lower in Japan (38.2 deaths/100,000 in 1985) than in the U.S. (72.2/100,000). The proportion of smokers is higher in Japan than in the U.S. since 1955. Japanese males start smoking considerably later than U.S. males, but smoke a higher quantity of cigarettes per day. Available information on inhalation practices and yield and type of cigarettes smoked showed no differences among the two countries large enough to account for the differences in mortality rates. Further data in this regard should be obtained. Dietary data show that fat consumption (as percentage of calories) is consistently higher in the U.S. than in Japan from 1950 (40% vs. 7.9%) through 1985 (43.5% vs. 24.5%). A linear relationship is observed between lung cancer mortality and fat intake. Our data support the hypothesis that dietary habits may modulate the carcinogenic effects of tobacco smoking.

Adult↗

PubMed1992

Production of basic fetoprotein in human peripheral lymphocytes during blastic transformation.

To clarify the significance of basic fetoprotein (BFP) in lymphocytes, we investigated whether BFP is produced in lymphocytes during blastic transformation. Peripheral blood lymphocytes obtained from 14 adults were cultured under the stimulation of lectins. The concentration of BFP in the culture medium (extracellular BFP) was estimated serially. The incorporation of [6-3H]-thymidine was assayed simultaneously. The intracellular BFP was measured by dual flow cytometry for DNA and BFP. A lymph node was studied immunohistochemically. Serum BFP was measured in four cases of lymphocytic leukaemia. In two cases, dual staining was performed. The intracellular BFP of the mitogen-stimulated lymphocytes was increased within 24 h. The extracellular BFP was increased exponentially from 72 h. The extracellular BFP at 96 h did not correlate with the [3H]-thymidine incorporation. The intracellular BFP increase began in G1 phase. Immunostaining showed that the B cells also produced BFP. The serum BFP level in leukaemia was high in 1 of 4 cases and the leukaemic cells in two cases showed high intracellular BFP content. These observations indicate that BFP is produced in activated human lymphocytes and in lymphocytic leukaemic cells. The production of BFP during blastic transformation will be a useful new in vitro model for studying the biological role of BFP, and BFP labelling may offer some new possibilities for the study of lymphocytes.

Adult↗

PubMed1992

Effect of alkylation with different sized substituents on thermal stability of lysozyme.

The amino groups of hen egg white lysozyme were reductively alkylated by the reaction with aliphatic aldehydes of various chain lengths and with two aldehydes of different steric hindrance at pH 7.5 and 4 degrees for 3 h. About four of the original six lysine residues were modified by the reaction with acetaldehyde, n-butylaldehyde or n-hexylaldehyde. About three lysine residues were 2,2-dimethylpropylated with trimethylacetaldehyde while a single residue was modified with benzaldehyde. The thermal stabilities of these alkylated lysozymes were investigated by differential scanning calorimetry (DSC) at different acidic pH values. Alkylation thermally destabilized the proteins, depending not only on the extent of modification but also on the size of the substituent. The alkylated derivatives were 8-19 kJ/mol less stable than native lysozyme at 25 degrees and pH 3.0. The temperature dependences of the activities of the alkylated lysozymes against ethylene glycol chitin indicated that the orders of the optimum temperatures and the maximum activities were exactly the same as the order of the thermal stabilities.

Aldehydes↗

PubMed1992

Adsorption of nafamostat mesilate by hemodialysis membranes.

The adsorption of the anticoagulant nafamostat mesilate (FUT-175) by five different hemodialysis membranes was studied in vivo and in vitro. In vivo, FUT-175 was adsorbed strongly by a polyacrylonitrile (AN69) membrane and slightly by another polyacrylonitrile (J-PAN) membrane but not by Cuprophan (CU), hemophan (HE), or polymethylmethacrylate (PMMA) membranes during hemodialysis performed in 4 patients in whom FUT-175 was used as an anticoagulant. Only during hemodialysis using the AN69 membrane did FUT-175 not induce a significant prolongation of celite-activated coagulation time. In vitro studies showed that FUT-175 was adsorbed by the AN69, J-PAN, and PMMA membranes but not by the CU and HE membranes. Methylene blue, a dye that possesses a cationic portion in its chemical structure, stained AN69, J-PAN, and PMMA membranes. Since FUT-175 also possesses a cationic portion, we conclude that FUT-175 is adsorbed by negatively charged membranes via an ionic bond and is unsuited for use as an anticoagulant in hemodialysis using an AN69 membrane because of that membrane's marked capacity to adsorb FUT-175.

Adsorption↗