Biomedical subjects

N Nishimura

Publications and source records attributed to N Nishimura.

At least 145 records · Page 8Linked to original sources

PubMed1993

Newly established human pancreatic carcinoma cell lines and their lectin binding properties.

Two human pancreatic carcinoma cell lines, designated HuP-T3 and HuP-T4, were established from the ascites of pancreatic cancer patients with carcinomatous peritonitis. The cell lines were grown in monolayer cultures and had population doubling times of 38.6 and 37.1 h, respectively. HuP-T4 secreted large amounts of CEA and CA19-9 into the medium, and HuP-T3 produced a small amount of CEA, but no CA19-9. Both cell lines showed tumorigenicity in nude mice. Histologically, the HuP-T3-derived tumor was poorly differentiated adenocarcinoma, and the HuP-T4-derived tumor was well differentiated papillotubular adenocarcinoma. In lectin histochemistry at both light and electron microscopic levels, the most striking difference between the lectin binding properties of the two cell lines and those of control normal pancreatic ductal cells was that soybean agglutinin (SBA) bound to both cell lines, but not to controls. These newly established cell lines should be useful models that will contribute to clarifying the biological and biochemical characteristics of pancreatic cancer.

Adenocarcinoma↗

PubMed1993

Improvement of culture conditions for L-proline production by a recombinant strain of Serratia marcescens.

Serratia marcescens SP511 was previously reported to be an L-proline-producing strain that harbors a recombinant plasmid carrying the mutant type of the proline operon. This strain produced 65 g/L of L-proline in a medium containing 22% sucrose and urea after 5 d of incubation under the conventional culture conditions. We searched for more suitable culture conditions for more abundant L-proline production by SP511. To improve the supply of a nitrogen source to cells, ammonium was used instead of urea and fed to a culture under control of the pH of the medium. The concentrations of MgSO4 and K2HPO4 were increased, and in addition, sucrose was continuously added to the culture at a final concentration of 32%. Under these conditions, the cell amount was increased twofold over that under the previous conditions and L-proline production reached a maximum of more than 100 g/L after 4 d of incubation.

Ammonia↗

PubMed1993

Cloning and DNA sequence of a 29 kilodalton polypeptide gene of Mycoplasma gallisepticum as a possible protective antigen.

A lambda gt11 clone, designated M1 and having a 0.8 kilobase (kb) insert, was selected by screening a Mycoplasma gallisepticum (M.g.) genomic DNA library with antisera against M.g. cells and their membrane proteins. The sequence of a 1.7 kb EcoRI fragment of genomic DNA covering the entire M1 insert revealed a long open reading frame, TM-1, that encoded a polypeptide with a deduced molecular weight of 29 kDa. An antiserum raised in chicken against the TM-1 polypeptide, which was produced by recombinant Escherichia coli cells and purified by column chromatography, inhibited growth of M.g. cells in vitro. Moreover, chickens immunized with this polypeptide were partially protected from a challenge with virulent M.g. This polypeptide may serve as the basis for a vaccine against M.g. infection.

Amino Acid Sequence↗

PubMed1993

Ileorectostomy or cecectomy but not colectomy abolishes the plasma cholesterol-lowering effect of dietary beet fiber in rats.

Adult male rats were fed a cholesterol-free diet with no added fiber (fiber-free) or with 10% cellulose or beet fiber. After 7 d of feeding, plasma total cholesterol concentrations were significantly lower in rats fed beet fiber than in those fed fiber-free or cellulose diets. This difference was due mainly to lower HDL cholesterol concentrations and remained significant for 28 d. The hypocholesterolemic effect of beet fiber relative to fiber-free disappeared when the cecum and colon were concurrently resected (ileorectostomy). Plasma cholesterol concentrations were the same in colectomized rats as in sham-operated rats fed the same diet and significantly lower in animals fed the beet fiber diet than in those fed the fiber-free diet. In cecectomized rats fed beet fiber, plasma cholesterol concentrations were intermediate between sham-operated rats fed the beet fiber diet and cecectomized or sham-operated rats fed the fiber-free diet. Fecal bile acid excretion was higher in rats fed the beet fiber diet than in those fed the fiber-free diet but did not correlate with plasma total cholesterol concentration. In rats with intact ceca, cecal total and individual short-chain fatty acids correlated negatively with plasma total cholesterol concentration. Dietary beet fiber lowers plasma cholesterol concentrations in rats, and the lower digestive tract, especially the cecum, seems to be necessary for this effect.

Animals↗

PubMed1993

Differential vasorelaxant effects of K(+)-channel openers and Ca(2+)-channel blockers on canine isolated arteries.

The vasorelaxant effects of the K(+)-channel openers, pinacidil and cromakalim, were compared with those of the Ca(2+)-channel blockers, verapamil and KB-2796 (1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine dihydrochloride), in canine isolated coronary, renal, basilar and mesenteric arteries precontracted with U46619, a thromboxane A2 mimetic. The relaxation induced by pinacidil and cromakalim was greater in coronary than in other arteries, the magnitude of relaxation being in the order of coronary > renal > basilar > mesenteric arteries. The relaxant responses to both drugs were inhibited by glibenclamide, a blocker of ATP-sensitive K+ channels. The relaxation induced by verapamil and KB-2796, in contrast, was greater in basilar than in other arteries, the magnitude of relaxation being in the order of basilar > coronary > renal and mesenteric arteries. In fura-2-loaded, U46619-stimulated arteries, pinacidil and cromakalim produced a greater reduction in intracellular Ca2+ concentration and muscle tension in coronary than in mesenteric arteries, while verapamil and KB-2796 reduced these values more potently in basilar than in mesenteric arteries. These results suggest that K(+)-channel openers exhibit a vasorelaxant selectivity for coronary arteries, whereas Ca(2+)-channel blockers exhibit such selectivity for cerebral arteries. The selective vasorelaxant action induced by these drugs appears to correspond, in part, to their effects on the concentration of intracellular Ca2+.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1993

Purification of a trypsin-type protease from human umbilical vein endothelial cells which is highly sensitive to the Kunitz inhibitor domain peptide of Alzheimer's disease amyloid protein precursor.

A trypsin-type protease was purified to enzymatic homogeneity from human umbilical vein endothelial cells by sequential affinity chromatographies. The enzyme specifically hydrolyzed dibasic substrates with leucine at the P3 positions, but scarcely hydrolyzed the other substrates tested. The enzyme was strongly inhibited by the Kunitz inhibitor domain peptide of Alzheimer's disease amyloid protein precursor (Ki value, 0.35 nM) and by the microbial inhibitors leupeptin and anti-pain. These results, together with a previous finding of a significant increase in the expression of Alzheimer's amyloid protein precursors (beta APPs) with the Kunitz inhibitor domain in Alzheimer's disease, suggest that the activity of the trypsin-type protease is suppressed by an increase of beta APPs with inhibitor activity in Alzheimer's disease, resulting in aberrant intracellular protein catabolism including degradation of beta APPs and beta-protein deposition.

Amino Acid Sequence↗

PubMed1993

Induction of metallothionein and its localization in the nucleus of rat hepatocytes after partial hepatectomy.

Metallothioneins, a group of cysteine-rich heavy-metal binding proteins, are induced in the regenerating rat liver in response to the stimuli evoked by partial hepatectomy. We have investigated the expression of metallothionein genes and proto-oncogenes (c-fos, c-jun and c-myc), as well as specific localization of metallothionein in the liver cells after partial hepatectomy. Metallothionein mRNA was detected as early as 3 hr and reached a maximal level by 6 hr. Expression of the proto-oncogenes apparently preceded the elevation of metallothionein protein because the latter was maximal 18 hr after partial hepatectomy, followed by a decrease until 70 hr. Hepatocytes of the intact rat liver have metallothionein in the cytoplasm only. Interestingly, metallothionein was localized predominantly in the nucleus as early as 6 hr after partial hepatectomy, and the staining intensity of metallothionein became maximal at 15 hr, followed by detection in both the cytoplasm and nucleus at 24 hr or longer. The use of a confocal laser scanning microscope with both tissue sections and isolated nuclei has clearly shown that metallothionein immunofluorescence exists inside hepatocyte nuclei after partial hepatectomy. Expression of the proto-oncogenes c-fos and c-jun is elevated after partial hepatectomy, and the resultant heterodimer of gene products may contribute to the observed metallothionein gene induction. However, the observation that metallothionein protein levels were elevated until 18 hr after partial hepatectomy suggests that an alternative pathway for the induction of metallothionein gene expression may also be present.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[Two cases of anaphylactoid reactions after intravenous methylprednisolone sodium succinate administration].

We have experienced two cases of anaphylactoid reactions following intravenous methylprednisolone sodium succinate administration. They had neither asthmatic nor other allergic histories. The first case was a 45-yr-old man. In addition to the antigenicity of hydrocortisone itself, it is suggested that administration speed was so fast that its side effects were intensified. The second case was a 10-yr old girl. Succinate ester was thought to be the cause of her allergic reaction (urticaria). It is also possible that her hypersensitivity to steroids was dose-dependent.

Anaphylaxis↗

PubMed1992

Secretion of autocrine growth-promoting activity by renal-carcinoma cells treated with 5-fluorouracil.

A study was made of the auto-proliferative activity of human renal-carcinoma cells in the supernatant from a carcinoma-cell culture in serum-free medium to which an anticancer agent had been added (5-FU). The human renal-cancer cells used in this study were of 3 strains: ACHN, VMRC-RCW and NT. When each line was cultured in medium containing no 5-FU, the supernatant showed almost no activity for stimulating DNA synthesis. However, when the line was cultured in the presence of 5-FU, the supernatant showed autocrine growth-promoting activity which strongly stimulated DNA synthesis of 3 renal-cancer cell lines in a dose-dependent manner. Activity could be detected in a 4- to 6-kDa fraction by gel filtration. This fraction increased the DNA-synthesis-promoting activity of epidermal growth factor, transforming growth factor-beta, basic fibroblast growth factor and insulin, and was acid- and heat-stable. It was also stable against pepsin and dithiothreitol. DNA synthesis in BALB/c 3T3, adult rat hepatocytes and rabbit renal tubular cells was not affected by this fraction which was thus considered not to affect non-cancerous cells. Renal-cell carcinoma responds poorly to anticancer agents, and the autocrine activity of the fraction may possibly be a factor accounting for this resistance.

3T3 Cells↗

PubMed1992

Improvement of nitrogen supply for L-threonine production by a recombinant strain of Serratia marcescens.

Serratia marcescens T-2000 was previously reported to be an L-threonine-producing strain that harbors the recombinant plasmid carrying the mutant-type threonine operon. This strain produced 55 g of L-threonine/L of the medium containing urea as a nitrogen source after 72 h of cultivation. In the urea-containing medium, transitory stop of the growth was observed during the early period of cultivation when the entire amount of ammonium ion formed from urea via heat decomposition disappeared in the medium. This indicated that the shortage of ammonium supply in cells might delay both the cell growth and the L-threonine production. The use of ammonia water as a nitrogen source for L-threonine production was therefore studied, because microbial cells generally assimilate this source more readily than urea. When ammonia water was automatically fed to the medium so as to maintain the pH of the medium at around 7, the growth was accelerated, and the L-threonine production reached a maximum of 65 g/L at 48 h. Under these conditions, sucrose, a carbon source, was continuously fed to the medium, resulting in the production of 100 g of L-threonine/L at 96 h. Thus, the L-threonine production of the recombinant L-threonine-producing strain could be increased by devising the method for supply of a nitrogen source.

Ammonia↗

PubMed1992

Detection of the thermostable direct hemolysin gene (tdh) and the thermostable direct hemolysin-related hemolysin gene (trh) of Vibrio parahaemolyticus by polymerase chain reaction.

Polymerase chain reaction (PCR) protocols were established for specific detection of the tdh and trh genes, the virulence marker genes of Vibrio parahaemolyticus encoding two related hemolysins. The tdh and trh genes are known to have sequence divergence of up to 3.3% and 16%, respectively. Attempts were made to find suitable primer pairs and annealing temperatures to detect each gene without fail. DNAs extracted from 36 representative strains of V. parahaemolyticus were used in the initial screening with various combinations of primer pairs and annealing temperatures. The combinations of primer pairs and annealing temperatures selected were then tested with DNAs extracted from 227 more strains of V. parahaemolyticus and from 133 bacterial strains belonging to 40 species other than V. parahaemolyticus. PCR protocols (primer pairs and annealing temperatures) were established that gave identical results to those obtained with the tdh- and trh-specific polynucleotide probes. These protocols established for the tdh and trh genes could detect 400 fg (100 cells) of cellular DNA carrying the respective gene. Spike experiments demonstrated that the sensitivities of the established PCRs were reduced by a factor of 10(4)-10(5) by an inhibitor(s) present in a normal faecal sample, indicating the need for either DNA extraction or enrichment of the faecal sample in alkaline peptone water for 4 h before the PCR of faecal samples.

Base Sequence↗

PubMed1992

Non-isotopic microtitre plate-based assay for detecting products of polymerase chain reaction amplification: application to detection of the tdh gene of Vibrio parahaemolyticus.

A non-isotopic microtitre plate-based assay method was devised for detection of products of the polymerase chain reaction. This assay involves affinity immobilization of the biotinylated amplification products in microtitre plate wells and their fluorescence detection by their hybridization with an oligonucleotide probe linked to alkaline phosphatase. An advantage of this procedure is that the immobilization and hybridization are carried out simultaneously in the wells, thus shortening the assay time. The assay method was applied to the detection of the tdh gene of Vibrio parahaemolyticus. Seven copies of the target chromosome could be detected in about 45 min after 35 cycles of amplification.

Alkaline Phosphatase↗

PubMed1992

Predation of Mansonia (Diptera: Culicidae) by native mosquitofish in southern Florida.

In experimental tanks and wading pools, the mosquitofish Gambusia holbrooki reduced densities of Mansonia larvae which, because of their attachment to the roots of aquatic plants, have been regarded previously as relatively impervious to predation. Exoskeletal remains of larval Mansonia were recovered from 43.5% of stomachs dissected from G. holbrooki, but not from Heterandria formosa (least killifish) collected from two undisturbed ponds covered with water lettuce (Pistia stratiotes L.). After 24 h in aquaria exposed to ambient light, predation by G. holbrooki reduced densities of Mansonia on water lettuce to one-third that of controls but in the dark, no significant differences were observed. In reduced light, densities of second- and fourth-instar Mansonia were reduced significantly after 1 wk of exposure to G. holbrooki. Video recordings of predation in aquaria revealed that G. holbrooki glean water lettuce roots to locate attached Mansonia and also capture free-swimming, dislodged larvae.

Animals↗

PubMed1992

First isolation of gamma-L-glutamyl-gamma-aminobutyric acid from bovine brains.

We had obtained some immunohistochemical indications which suggested that peptide(s) containing GABA at the C-terminal could exist in specific neurons in brains. We therefore sought such GABA conjugate(s) by isolating an acidic GABA-dipeptide from bovine brains and determined its structure as gamma-L-glutamyl-gamma-aminobutyric acid (gamma-L-Glu-gamma Abu:GluGABA). Its gamma-linkage was determined by a mass-spectrometric (B/E linked scan SIMS) analysis; its chirality was established by a chiral column HPLC technique. This peptide is the first acidic GABA-peptide recognized in brain and the first brain peptide containing GABA at the C-terminal.

Animals↗

PubMed1992

Monoclonal antibodies recognising pol and env proteins of mammalian retroviruses.

Mouse monoclonal antibodies were generated for three 20- to 23-mer synthetic peptides whose amino acid sequences were highly conserved in the pol or env regions of 14 mammalian and two avian retroviruses. By Western-blot analysis, these antibodies recognised the epitopes in major and minor pol or env proteins of six mammalian type-C and -D retroviruses. One of the anti-env monoclonal antibodies was found to recognise all the env transmembrane proteins of six mammalian retroviruses examined.

Amino Acid Sequence↗

PubMed1992

Localization of metallothionein in the brain of rat and mouse.

Metallothionein (MT) is a low molecular mass protein inducible by heavy metals such as cadmium (Cd), zinc, and copper, and having high affinity for these metals. In the present study, we investigated the immunohistological localization of MT in the brains of rats and mice. In adult rat brain, almost no MT immunostaining was observed, whereas in adult mouse brain strong MT immunostaining was found in the ependymal cells, some glial cells, arachnoid, and pia mater. No immunostaining was detected in neurons and endothelial cells. In younger rats (1-3 weeks old), strong MT immunostaining was observed in ependymal cells, choroid plexus epithelium, arachnoid, and pia mater. The overall MT concentration in adult mouse brain appeared higher than that of the brains of young and adult rats. When adult rats were administered Cd, MT was induced not only in some glial cells, ependymal cells, arachnoid, and pia mater but also in endothelial cells. Although Cd treatment resulted in an increase in the MT immunostaining in the specific cells described above, the MT induction was not great enough to significantly affect the overall MT level in the brain. The present result suggest a possible link of MT with cell growth of choroid plexus epithelium and ependymal cells, as well as a detoxifying role of MT in the blood-brain barrier and the cerebrospinal fluid-brain barrier.

Aging↗

PubMed1992

[Effect of AS-4370 on gastric motility in patients with diabetic autonomic neuropathy].

Delayed gastric emptying in diabetic patients occurs with progress of automatic neuropathy as one late complication. Delayed emptying is deeply correlated with poor glycemic control, due to imbalance between nutrients absorption and effect of exogenous insulin. AS-4370 is a newly developed prokinetic agent which has been reported to selectively activate motility of the upper gastrointestinal tract through enhancing acetylcholine release from nerve terminals within the enteric mural plexus. In this study, we evaluated the effect of AS-4370 on gastric motility in diabetic patients with autonomic neuropathy. Eight diabetic patients with autonomic neuropathy (3 males and 5 females) with mean age of 56 years old (range 29-66) participated to this study after giving written informed consent. Gastric motility was evaluated by gastric emptying and electrogastrography. Gastric emptying study was done using 99mTc-Tin colloid labeled omelet meal served with 2 slices of toast and 200 ml of milk. Electrogastrography was recorded from epigastric skin surface, for 30 minutes before and after meal each. AS-4370, 7.5 mg tid, was given for four weeks after basal recording of gastric motility studies. Following the 4-week treatment with AS-4370, gastric motility studies were repeated. For the motility studies after medication, drug was given 30 minutes before test meal. Gastric retention rate at 150 minutes in all patients were over 45% of upper limit of normal range in basal study with mean value of 69 +/- 5%, which decreased significantly to 52 +/- 5%, with AS-4370 treatment (p < 0.01). Gastric emptying speed, another parameter for gastric emptying also improved with medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Hemodynamic difference accounted for the orientation of a Björk-Shiley mitral prosthesis: a color Doppler echocardiographic study].

To determine whether the orientation of the major orifice of a mitral tilting disc prosthesis affects hemodynamics, intracavitary blood flow patterns were studied in 45 patients with well-functioning Björk-Shiley mitral prosthesis using color Doppler flow imaging. The major orifice was oriented towards the septum in 23 patients (12 men, 11 women, age 58 +/- 11 years; group S), and towards the posterior wall in 22 patients (8 men, 14 women, age 55 +/- 9 years; group P). 1) The left ventricular end-diastolic dimensions (S: 4.8 +/- 0.9 cm, P: 5.2 +/- 1.0 cm), end-systolic dimensions (S: 3.6 +/- 0.9 cm, P: 3.8 +/- 1.2 cm), and left atrial dimensions (S: 5.0 +/- 1.0 cm, P: 4.7 +/- 0.9 cm) did not differ significantly between the 2 groups. 2) The peak mitral flow velocities (S: 1.43 +/- 0.38 m/sec, P: 1.43 +/- 0.27 m/sec), pressure gradients (S: 8.5 +/- 4.0 mmHg, P: 8.4 +/- 3.1 mmHg), and pressure half-times (S: 94.0 +/- 19.0 msec, P: 86.5 +/- 21.7 msec) did not differ significantly between the 2 groups. 3) Although mitral regurgitation was detected in 8 patients (35%) in the S group and in 2 patients (9%) in the P group, hemodynamically significant regurgitation was detected in only 4 patients in the S group (3 mild, one moderate). 4) The patients in the S group had reversed intracavitary blood flow; mitral flow was first directed towards the left ventricular outflow tract during diastole, while the outflow pattern was displaced into the left ventricular inflow tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗