Biomedical subjects

K Adachi

Publications and source records attributed to K Adachi.

At least 235 records · Page 13Linked to original sources

PubMed1997

Histopathological study on bone changes induced by recombinant granulocyte colony-stimulating factor in rats.

Histopathological bone changes were examined in growing rats intravenously administered with high doses (100 and 1000 micrograms/kg/day) of recombinant human granulocyte colony-stimulating factor (rG-CSF) for 28 days. The changes were observed in the region where physiological bone resorption actively occurs in the growth phase, that is the trabeculae of metaphyseal spongy bone and the endosteum region of diaphyseal compact bone. Histologically, the changes involved accelerated osteoclastic bone resorption and osteogenesis due to intramembranous ossification. While osteoclastic bone resorption was observed in almost all lesions, about half of which were accompanied by osteogenesis. Bone changes which appeared after administration of rG-CSF were characterized by frequent occurrence at the site of highly osteoclastic activity and by initial osteoclastic resorption followed by osteogenesis due to intramembranous ossification. These results suggest that the main action of rG-CSF on bone may be an acceleration of osteoclastic bone resorption.

Animals↗

PubMed1997

Effects of gamma-butyric acid on the release of thyrotropin-releasing hormone from the rat retina in vitro.

Effects of gamma-butyric acid (GABA) on the release of thyrotropin-releasing hormone (TRH) from the rat retina in vitro were studied. The rat retina was incubated in medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (medium). The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat retina was inhibited significantly in a dose-related manner with the addition of GABA, but not with bicuculline. The inhibitory effect of GABA on TRH release from the retina was blocked by adding bicuculline to the medium. The findings suggest that the GABAergic system inhibits TRH release from the rat retina in vitro.

Animals↗

PubMed1997

Functional and phenotypical activation of leucocytes in inflamed human colonic mucosa.

Infiltrating leucocytes are activated to generate reactive oxygen species or to produce several molecules in inflamed colonic mucosa. To clarify the phenotypical and functional properties of activating cells in colitic mucosa, 23 patients with ulcerative colitis and 13 controls were studied using a combined method for determining in situ nitroblue tetrazolium reducing activity and immunohistochemical characterization. Antibodies 25F9 (anti-macrophage), EG2 (anti-eosinophil cationic protein), MAC387 (anti-calprotectin, expressed by activated myeloid-histiocytes lineage), and MAC-1 (anti-CD11b) were used. The proportion of EG2, calprotectin, and CD11b-positive cells were significantly increased in inflamed mucosa. The proportion of EG2, calprotectin, and CD11b-positive cells significantly correlated with the histological degree of inflammation. Proportion of EG2-positive cells but not calprotectin nor CD11b-positive cells was significantly correlated with nitroblue tetrazolium reducing activity. Aggregated cells reducing nitroblue tetrazolium seen in severely inflamed mucosa were found to be EG2 positive. Most of the calprotectin-positive cells were 25F9 negative. In addition to activation of neutrophils and macrophages, eosinophil activation has been shown to be involved in inflamed colonic mucosa.

Adolescent↗

PubMed1997

Determination of local brain glucose level with [14C]methylglucose: effects of glucose supply and demand.

Methylglucose can be used to assay brain glucose levels because the equilibrium brain-to-plasma distribution ratio for methylglucose (Ce*/Cp*) is quantitatively related to brain (Ce) and plasma (Cp) glucose contents. The relationship between Ce and Ce*/Cp* predicted by Michaelis-Menten kinetics has been experimentally confirmed when glucose utilization rate (CMRGlc) is maintained at normal, resting levels and Cp is varied in conscious rats. Theoretically, however, Ce and Ce*/Cp* should change when CMRGlc is altered and Cp is held constant; their relationship in such conditions was, therefore, examined experimentally. Drugs were applied topically to brains of conscious rats with fixed levels of Cp to produce focal alterations in CMRGlc, and Ce and Ce*/Cp* were measured. Plots of Ce as a function of Ce*/Cp* for each Cp produced straight lines; their slopes decreased as Cp increased. The results confirm that a single theoretical framework describes the relationship between Ce and Ce*/Cp* as either glucose supply or demand is altered over a wide range; they also validate the use of methylglucose to estimate local Ce under abnormal conditions.

Animals↗

PubMed1997

The cessation of fluoridated water administration and the fluoride distribution profiles in rat molar cementum.

The aim of this work was to obtain further information about the origin of fluoride profiles in cementum. Fluoride was administered to rats at varying doses (0.50, 100 ppm F in drinking water) and for different durations (4, 13 and 25 weeks). Fluoride distribution across the full thickness of molar cementum in rats was measured by means of an abrasive micro-sampling technique. The average fluoride concentrations in cementum increased significantly with increasing dose and duration of fluoride administration. The relative reduction of the average fluoride concentrations after cessation of fluoride administration was 94.2-36.5% at 50 ppm F and 62.2-49.2% at 100 ppm F in the outer layers (1-60 microns) and 91.5-24.1% at 50 ppm F and 74.1-7.6% at 100 ppm F in the middle (61-120 microns) layers of the cementum, respectively. The reduction rates were more closely related to the time intervals following cessation rather than fluoride concentrations in drinking water or specificity within the cementum. Two factors which may influence this are new cementum formation after withdrawal of fluoride and some fluoride release from cementum surfaces when the fluoride supply stopped. It was concluded that the cessation of fluoride administration reduced the fluoride concentration on the outer layers of cementum differing from bone where reduction occurs across the entire thickness.

Analysis of Variance↗

PubMed1997

Alternative signaling mechanism of leukemia inhibitory factor responsiveness in a differentiating embryonal carcinoma cell.

Leukemia inhibitory factor (LIF) is a cytokine that plays an important role during mouse embryogenesis. We showed that adenovirus E1A represses the interleukin-6 signal transduction pathway that uses the same JAK tyrosine kinase and STAT (signal transducer and activator of transcription) transcription factor as LIF. Here, we report that the LIF-JAK-STAT signal transduction pathway is blocked in cellular E1A-expressing undifferentiated F9 cells, and that the block is overcome by retinoic acid-induced differentiation. LIF failed to stimulate the expression of the acute phase response element (APRE)-driven luciferase gene in undifferentiated F9 cells, whereas the luciferase activity was remarkably increased by LIF treatment in differentiated F9 (dF9) cells. We analyzed the mechanism of the APRE regulation and found that the LIF-induced APRE-binding activity was regulated in a differentiation-dependent manner. The protein levels and the tyrosine phosphorylation of JAK1, JAK2, and STAT3 in F9 cells were not different from those in dF9 cells. The exogenous expression of activated c-Ha-ras partially recovered the LIF responsiveness of the APRE-luciferase gene in F9 cells, but the dominant negative ras N-17 did not repress the LIF-induced activation of APRE-luciferase in dF9 cells. These results suggested that an unknown coactivation process that is partially compensated by Ras is required for STAT3-APRE binding in F9 cells.

Acute-Phase Proteins↗

PubMed1997

Values of the serum components in Japanese black beef steers at farms with high productivity and low frequencies of disease and death in Miyazaki Prefecture.

Few reference values for use in metabolic profile tests for the maintenance of high productivity and the prevention of production diseases have been reported in Japanese Black beef cattle. To obtain basic data, 101 healthy steers at farms with high productivity and low frequencies of disease and death in Miyazaki Prefecture, Japan, were examined for the values of their serum components in this preliminary study. At the later fattening stage (5 to 20 months after introduction), statistically significant increases were observed in the mean serum activities of lactic dehydrogenase, glutamic-oxalacetic transaminase, gamma-glutamyl transpeptidase, and creatine phosphokinase, the mean serum contents of triglyceride, total cholesterol, albumin (Alb), total protein, blood urea nitrogen, magnesium, and vitamin E, and the mean serum calcium (Ca)/inorganic phosphorus (IP) ratio, and statistically significant decreases were seen in the mean serum alkaline phosphatase activity and the mean serum contents of glucose, IP, and vitamin A. The mean serum Alb/globulin ratio and the mean serum Ca and nonesterified fatty acids contents demonstrated no statistically significant changes.

Alkaline Phosphatase↗

PubMed1997

Plasma levels of brain natriuretic peptide as an index for evaluation of cardiac function in female gene carriers of Duchenne muscular dystrophy.

The level of plasma brain natriuretic peptide (BNP) was elevated in 8 of 15 female gene carriers of Duchenne muscular dystrophy (DMD), and the level correlated with indices of cardiac function. In one of these carriers, whose clinical course was followed for one year, the plasma BNP level was elevated before the development of cardiac symptoms, further increased with the evolution of cardiac symptoms, and then decreased after treatment for cardiac failure. These results suggest that the plasma BNP level may be useful for the early detection of cardiac dysfunction and for evaluating the efficacy of cardiac treatment in female DMD carriers.

Adult↗

PubMed1997

Effects of YM-14673, a thyrotropin-releasing hormone analogue, injected into the shell and the core of the nucleus accumbens on production of repetitive jaw movements in rats: comparison with the effects of a dopamine D1 and D2 receptor agonist combination.

The present study examined whether the shell and the core of the nucleus accumbens play a differential role in the display of YM-14673-induced jaw movements in rats. For that purpose the effects of YM-14673 were compared to those of a SKF 82958 and quinpirole combination, a dopamine D1 and a D2 receptor agonist respectively, that is known to functionally differentiate these two subregions of the nucleus. Consistent with the previous report, bilateral injections of a mixture of SKF 82958 (5 micrograms) and quinpirole (10 micrograms) into the shell of the nucleus accumbens produced repetitive jaw movements, whereas similar injections of the mixture into the core did not induce such an effect. In contrast, there was no regional difference in the effects of YM-14673 on the production of repetitive jaw movements. Thus, both bilateral injections of YM-14673 (0.1 or 1.0 microgram) into the shell or the core produced similar repetitive jaw movements in a dose-related manner. Moreover, the pattern of oral movements induced by YM-14673 differed from that induced by the mixture of SKF 82958 and quinpirole; frequent tongue protrusions were evident in rats treated with the mixture but were not seen in YM-14673-treated rats. It therefore appears that, unlike the effects of the mixture of dopamine D1 and D2 receptor agonists, the effects of YM-14673 in the shell on the production of rat jaw movements do not differ from the effects of the compound in the core.

Animals↗

PubMed1997

Helicobacter pylori infection accelerates gene expression of glicentin in the gastric mucosa. Its association with intestinal metaplasia of the stomach.

BACKGROUND: Glicentin is an intestinal polypeptide hormone which seems to promote intestinal metaplasia (IM) in the gastric mucosa. The aim of this study was to clarify whether Helicobacter pylori infection accelerates glicentin gene expression. METHOD: Glicentin mRNA was investigated by reverse-transcription polymerase chain reaction using gastric biopsies from 47 patients examined endoscopically and denying IM. RESULTS: IM was observed in 18 (38.3%) cases histologically, but not in the other 29 (62.7%). Glicentin mRNA was significantly correlated with histological IM (P < 0.01) and was positively correlated with H. pylori infection (P < 0.05). CONCLUSION: Our results indicate that H. pylori infection is associated with the induction of glicentin in the gastric mucosa, thus supporting the hypothesis that H. pylori infection accelerates IM of the stomach.

Adult↗

PubMed1997

Hb Osler [beta 145(HC2)Tyr-->Asp] results from posttranslational modification.

We studied two members of an African American family with erythrocytosis. An abnormal hemoglobin variant with an electrophoretic pattern on cellulose acetate similar to Hb J was identified. The oxygen dissociation curve using whole blood was biphasic, dramatically left-shifted, and hyperbolic. Sequence analysis of DNA from the proband showed heterozygosity for a T-->A change at the first position of codon 145 in the beta-globin gene which results in the substitution of an asparagine residue for normal tyrosine. The second cycle of C-terminal amino acid sequence analysis of a mixture of alpha- and beta-globin chains showed tyrosine, aspartic acid, and small amounts of asparagine. Collectively, these results indicate the existence of a mutation at codon 145 of the beta-globin gene which encodes for asparagine instead of tyrosine, and that asparagine then undergoes a partial posttranslational deamidation to aspartic acid. This amino acid substitution corresponds to Hb Osler, which is a high oxygen affinity hemoglobin variant, initially described to be caused by a substitution of Tyr-->Asp at beta 145. Posttranslational amino acid modification may constitute an important component in the pathophysiology of hemoglobinopathies.

Adult↗

PubMed1997

New anticancer antibiotics pelagiomicins, produced by a new marine bacterium Pelagiobacter variabilis.

In the course of our screening for new anticancer compounds produced by marine bacteria, we found that a new genus marine bacterium Pelagiobacter variabilis produced new phenazine antibiotics, pelagiomicins A, B and C. Those compounds were labile in water and alcohols. The absolute structure of the main component, pelagiomicin A, and the structures of the minor ones were determined from the spectroscopic data and by synthesis. Pelagiomicin A exhibits activity against Gram-positive and -negative bacteria and antitumor activity in vitro and in vivo.

Antibiotics, Antineoplastic↗

PubMed1997

Hydroxyakalone, a novel xanthine oxidase inhibitor produced by a marine bacterium, Agrobacterium aurantiacum.

A new xanthine oxidase inhibitor named hydroxyakalone was isolated from the culture broth of a marine bacterium Agrobacterium aurantiacum N-81106. Structure of hydroxyakalone was determined to be 4-amino-1H-pyrazolo[3,4-d]pyrimidine-3-one-6-ol by the spectral studies of hydroxyakalone and its permethyl derivative. The concentration to induce 50% inhibition (IC50) was 4.6 microM against xanthine oxidase.

Enzyme Inhibitors↗

PubMed1997

Korormicin, a novel antibiotic specifically active against marine gram-negative bacteria, produced by a marine bacterium.

A novel antibiotic named korormicin was isolated from the marine bacterium, Pseudoalteromonas sp. F-420. This strain was isolated from the surface of a macro alga Halimeda sp. collected from Palau (the Republic of Belau). The planar structure of korormicin was determined by the result of 2D NMR studies and mass spectral data. Korormicin had specific inhibitory activity against marine Gram-negative bacteria, but was inactive against terrestrial microorganisms.

Anti-Bacterial Agents↗

PubMed1997

Organ distribution of iodide transporter (symporter) in the rat: immunohistochemical study.

Iodide transporter/symporter (NIS) was identified immunohistochemically in rat tissues using specific antipeptide serum. Anti-NIS serum was raised in New Zealand white rabbits immunized with a conjugate of synthetic NIS peptide (39-53) with bovine serum albumin. Immunohistochemical analysis was performed by avidine-biotin complex method. NIS immunoreactivity was visualized in the thyroid gland, gastric and small intestine mucosa, anterior pituitary, adrenal medulla, pancreatic islets, kidney, chorioid plexus and several brain and spinal cord nuclei. When using antiserum preincubated with synthetic NIS peptide (39-53) or rat thyroid homogenate containing NIS, no significant stain of the thyroid gland was detected. These findings suggest that NIS is widely distributed and that the method used is suitable for studying the distribution of NIS in rats.

Journal Article↗

PubMed1997

[Treatments for T4 advanced lung cancer with invasion to the superior vena cava].

We discussed on the treatments for T4 lung cancer with invasion to the superior vena cava, whose prognosis has been poor. However, surgical resection may improve the prognosis compared with radiation therapy. The prosthetic replacement of superior vena cava can be done safely, and its patency is good in cases of ring-enforced ePTFE graft. Although superior vena caval obstruction syndrome had been a hard issue in the advanced cases, stenting in superior vena using the interventional radiological technique is a safe and reliable method. We should consider the stenting as the first choice for superior vena cava obstruction syndrome, because it makes the QOL improve so much.

Adult↗

PubMed1996

Expression of soluble human beta-globin chains in bacteria and assembly in vitro with alpha-globin chains.

Authentic soluble human beta-globin chains were produced in Escherichia coli using an expression plasmid (pHE2beta) containing full-length cDNAs coding for human beta-globin chain and methionine aminopeptidase. Spectral properties of the purified beta-globin were identical to those of authentic beta-globin. Soluble beta-globin showed low (16 kDa) and high molecular mass (32 kDa) forms that could be separated by gel filtration chromatography. SDS-polyacrylamide gel electrophoresis and electrospray mass spectrometry revealed the 32-kDa species was dimeric beta-globin formed by an intermolecular disulfide bond, while the 16-kDa species was authentic monomeric beta-globin. Monomeric forms of beta-globin, like authentic native beta-globin, formed tetrameric hemoglobin (Hb) A (alpha2beta2) in vitro upon incubation with alpha-globin, while dimeric forms did not. When beta-globin dimers, however, were converted to monomers by incubation with dithiothreitol, the beta-globin chain monomers assembled with alpha-globin and formed hemoglobin tetramers. alpha-Globin was more thermally unstable than beta-globin, while assembled tetramers promoted higher stability. Disulfide-bonded beta-globin dimers showed a slight increase in thermal stability compared with beta-globin; however, dimers were still more unstable than tetrameric Hb A. These results indicate that presence of alpha chains favors assembly with beta-globin, beta-beta dimers cannot bind alpha chains, and that Hb A tetramer formation results in the most thermally stable species.

Biopolymers↗

PubMed1996

Expression studies of delta-globin gene alleles associated with reduced hemoglobin A2 levels in Greek Cypriots.

We previously identified five delta-globin gene alleles associated with reduced hemoglobin (Hb) A2 (Trifillis, P., Ioannou, P., Schwartz, E., and Surrey, S. (1991) Blood 78, 3298-3305). We have now evaluated functional consequences of the changes after expression in COS-1 cells to monitor effects on RNA splicing. In addition, variant Hb A2 tetramers were expressed in yeast to assess effects of amino acid changes on oxygen binding and stability to heat and mechanical agitation. The G --> T change at codon 27 and the A --> G change in IVS-2 both affect RNA splicing, whereas the C --> T change at codon 97 and the AT deletion in IVS-2 have no effect. Oxygen equilibrium curves of the Hb A2 variants expressed in yeast were similar to that of wild type Hb A2. None of the three variant Hb A2 tetramers (Thr --> Ile at codon 4 (Hb deltaT4I), Ala --> Ser at codon 27 (Hb deltaA27S), and Arg --> Cys at codon 116 (Hb deltaR116C)) showed decreased heat stability compared with Hb A2, whereas the Hb deltaT4I variant showed highest instability to mechanical agitation. Co-expression in yeast of alpha-globin chain and the delta-chain variant containing a Leu --> Pro change at codon 141 yielded no identifiable tetramers, suggesting lack of assembly or severe tetramer instability. These studies show the probable cause for decreased Hb A2 for two alleles is due to defective splicing, whereas decreased protein stability, increased tetramer association with red cell membranes, increased interdisulfide bond formation of delta-chains, which inhibits assembly with alpha-chains, and/or reduced assembly is suggested for the other three alleles.

Alleles↗