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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 919 records · Page 51Linked to original sources
PubMed1994

Concentration of interleukin-1 beta correlates with prostaglandin E2 and F2 alpha in human pre-ovulatory follicular fluid.

To investigate the role(s) of interleukin-1 beta (IL-1 beta) in human ovarian function, we measured the concentrations of IL-1 beta, prostaglandins (PGs) and steroids in follicular fluid of 90 stimulated ovaries, with reference to oocyte maturation. Concentrations of IL-1 beta were significantly higher in the follicles from which mature oocytes were recovered than in follicles from which oocytes could not be recovered (P < 0.05). IL-1 beta concentrations also increased in association with oocyte maturation. Positive significant correlations were seen between IL-1 beta and prostaglandin E2 (PGE2) (r = 0.47, P < 0.001), and between IL-1 beta and prostaglandin F2 alpha (PGF2 alpha) (r = 0.22, P < 0.05) in pre-ovulatory follicular fluid, but not between IL-1 beta and oestradiol, or between IL-1 beta and progesterone. Follicular fluid IL-1 beta might contribute to prostaglandin-induced oocyte maturation and ovulation.

Cellular Senescence↗
PubMed1994

Co-localization of placental lactogen-I, placental lactogen-II, and proliferin in the mouse placenta at midpregnancy.

This study was undertaken to determine whether mouse placental lactogen (mPL)-I, mPL-II, and proliferin (PLF) are expressed by the same population of placental giant cells at midpregnancy. Tissue sections from Day 9 of pregnancy were analyzed by double immunofluorescence staining. Sections were stained for PLF by use of a rhodamine-conjugated second antibody, and for mPL-I or mPL-II by use of a fluorescein-conjugated second antibody. All three proteins were present in most of the same giant cells. The distribution of mPL-I and PLF among giant cells in vitro was also examined. When placental cells from Day 7 of pregnancy were cultured for 5 days, > 90% of the cells that immunostained for mPL-I also immunostained for PLF on the first 3 days of culture. Thereafter, the percentage of cells that contained both proteins declined rapidly while the percentage that contained only PLF increased, suggesting continued differentiation of the cells in vitro. These data demonstrate that the same trophoblast giant cells express mPL-I, mPL-II, and PLF simultaneously at midpregnancy, suggesting that their gestational profiles in maternal blood during this period result at least partly from changes in gene expression in one population of cells and not from differentiation of several subsets of giant cells, each expressing only one member of the gene family.

Animals↗
PubMed1994

Mouse placental cells secrete immunoreactive growth hormone-releasing factor.

The initial objective of this study was to establish a placental cell culture system in which the secretion of mouse growth hormone-releasing factor (mGHRF) could be examined during a several-day period. To determine when during pregnancy placental cells begin to express mGHRF, Northern blot analysis was carried out on total RNA from placentas collected on Days 6, 9, 11, 13, 15, 17, and 18 of pregnancy. Mouse GHRF mRNA could be detected as early as Day 11 of pregnancy. Its steady-state levels increased to maximum values on Days 15-17 and then declined slightly on Day 18. Placentas from Day 12 of pregnancy were selected for cell culture. The basal zone and labyrinth were dispersed in collagenase, and the cells were fractionated on a Percoll gradient. Two bands of cells were selected for further study. Both released significant amounts of immunoreactive mGHRF during a 5-day culture period. Effects of prolonged exposure of the cells to 8-bromo-cAMP and to agents that elevate intracellular cAMP concentration were then examined. Treatment of the cells with 0.5 mM 8-bromo-cAMP resulted in a significant decrease in the mGHRF concentration of the medium by the second day of culture. Mouse GHRF secretion was also inhibited by treatment of the cells with 100 ng/ml cholera toxin or 0.1 mM forskolin. The effect of 8-bromo-cAMP was concentration-dependent, with 0.1 mM being the lowest concentration that was active. 8-Bromo-cAMP treatment also reduced the steady-state level of mGHRF mRNA in the cells.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Selective delivery of a greater amount of methotrexate to regional lymph nodes using a new dosage formulation, methotrexate adsorbed on activated carbon particles, in rats.

A new dosage formulation (MTX-CH) comprising methotrexate (MTX) adsorbed onto a suspension of activated carbon particles was developed for the treatment of lymph node metastases. In vitro studies showed that activated carbon particles adsorbed a great amount of MTX. Subcutaneous injection of MTX-CH into the left hind foot pad of rats distributed a greater amount of MTX selectively to the regional lymph nodes (the left popliteal node and the para-aortic nodes) for a longer period of time than similar administration of MTX aqueous solution with a smaller amount of MTX distributed to the rest of the whole body.

Adsorption↗
PubMed1994

Sexual agglutination substances require a 'carrier' glycoprotein for integration into the cell wall of Saccharomyces cerevisiae.

Sexual agglutination, caused by agglutination substance (AS) on a and alpha cell walls, is the first indispensable step of the mating reaction in ascosporogenous yeasts including Saccharomyces cerevisiae. The AS biosynthetic process in S. cerevisiae was investigated by pulse label-chase experiments with analysis by polyacrylamide gel electrophoresis (PAGE) for 16 h in the presence of urea. Because of its low mobility, AS can be separated from other proteins by prolonged PAGE. Nascent AS was integrated into cell walls after it linked covalently to a 'carrier' glycoprotein. The results suggest that the 'carrier' is synthesized stepwise through three distinct precursors (III-->II-->I). The 'carrier' glycoprotein (I) and its precursors (II, III) were synthesized in both a, alpha haploid and a/alpha diploid cells. The N-glycosylation linkage inhibitor, tunicamycin, and protein synthesis inhibitor, puromycin, inhibited the III to I maturation. The results indicated that both the 'carrier' and the nascent active site of AS linked to the 'carrier' are integrated into the wall in a haploid cell while the 'carrier' alone is integrated in a diploid cell.

Agglutinins↗
PubMed1994

Effects of strong pulsed magnetic fields on the cardiac activity of an open chest dog.

The heart of an open chest dog was stimulated by strong magnetic fields which were damped sinusoidal pulses with the one-cycle period of 1.47 ms. Stimulation effects were detected by electrocardiograph (ECG) and arterial blood pressure as a function of the strength of the field, the triggering point in the cardiac cycle, and the position of a stimulating coil. The threshold for arrhythmias was a minimum for the stimuli triggered at the apex of the T wave and on the P wave in the ECG. Premature ventricular and premature atrial contractions occurred according to whether the coil was placed over the ventricles or the atria. Ventricular defibrillation can not be attained by the magnetic stimulus with the flux density of 9.2 T which was the maximum field used.

Animals↗
PubMed1994

S100-positive histiocytes in T-cell-dependent area in human lymph nodes express P-glycoprotein.

In the present study, we examined P-glycoprotein (P-gp)-expressing cells in human lymph nodes (LN) from patients with reactive lymph adenitis and various malignant lymphomas (ML). MDR1 mRNA was detected in all reactive LN and in 8 of 10 ML samples examined by reverse transcription polymerase chain reaction (RT-PCR). The signal intensity of the bands was stronger in samples from T-cell ML LN than in those from LN of reactive lymph adenitis and B-cell ML. Immunohistochemistry also showed positive reactivity with cellular components in the LN. The P-gp-positive cells, detected by UIC2, in reactive lymph adenitis and ML samples were large in size in the T-cell-dependent paracortical area in LN. Further, morphological characteristics were similar in UIC2-positive cells between reactive and ML LN. Double staining with UIC2 and a hematopoietic cell lineage-specific monoclonal antibody showed that UIC2-positive cell co-expressed S-100, but not other lymphocyte- and ML cell-specific antigens, indicating that these cells correspond to histiocytes in the T-cell-dependent paracortical area. Our results show that P-gp was expressed in histiocytes but not ML cells in LN, and suggest that this molecule may play an important role in the biological function of histiocytes and/or for maintenance of homeostatic levels in T-cell ML LN.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

PRAD1 gene over-expression in mantle-cell lymphoma but not in other low-grade B-cell lymphomas, including extranodal lymphoma.

Employing Northern blot analysis and the polymerase chain reaction, we investigated PRAD1 gene overexpression in the tumour tissues of 58 patients with B-cell lymphoma. These findings were then examined in relation to the patients' clinical and immunohistological characteristics. The over-expression of this gene was detected in 6/8 patients with mantle cell lymphoma (MCL) and in only 1/50 other lymphomas, indicating its close association with MCL. The patients with MCL had common clinical findings of advanced disease with generalized lymphadenopathy on admission, and they had a CD5+CD10-IgD+ phenotype. The patients with chronic lymphocytic leukaemia (CLL) also showed findings indicating a distinctive disease entity: a CD5+CD10-IgD+ phenotype and lack of PRAD1 over-expression. In contrast, most patients with diffuse low-grade lymphoma other than MCL and CLL had localized extranodal disease, expressed a CD5-CD10-IgD- phenotype, and lacked PRAD1 over-expression. These findings suggest that extranodal low-grade lymphomas differ from nodal MCL and are not part of the spectrum of CLL.

Base Sequence↗
PubMed1994

Endotoxin and pro-inflammatory cytokines stimulate endothelin-1 expression and release by airway epithelial cells.

Endothelin is a potent bronchoconstrictor peptide first identified as a novel vasoconstrictor produced by vascular endothelial cells. Recent reports suggest that airway epithelial cells are also capable of releasing this active peptide. To investigate the regulatory mechanism of endothelin expression, we studied the effects of endotoxin and pro-inflammatory cytokines such as interleukin-1 and tumour necrosis factor on the expression and release of endothelin-1 by airway epithelial cells. Both endotoxin and the cytokines stimulated endothelin-1 release by human bronchial epithelial cells. Northern blot analysis showed increased expression of preproendothelin-1 mRNA by these factors. These results suggested that airway epithelial cells might play a role in the local airway smooth muscle tone through the production of endothelin, which might be upregulated by inflammatory products in the airways.

Aged↗
PubMed1994

Elevation of serum soluble intercellular adhesion molecule-1 (sICAM-1) and sE-selectin levels in bronchial asthma.

Adhesion molecules such as ICAM-1 and E-selectin have been shown to play important roles in the production of allergic inflammation. In the present study, we measured serum soluble ICAM-1 (sICAM-1) and soluble E-selectin (sE-selectin) levels by ELISA in 42 patients with bronchial asthma (22 atopic and 20 non-atopic) during asthma attacks and in stable conditions in order to assess the state of ICAM-1 and E-selectin in allergic inflammation. Both serum sICAM-1 levels and serum sE-selectin levels in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. These findings were observed regardless of atopic status. To examine the regulatory mechanism in the elevation of serum sICAM-1 and sE-selectin levels, serum tumour necrosis factor-alpha (TNF-alpha) levels were measured by ELISA. TNF-alpha levels in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. There was a correlation between the nature of change in serum TNF-alpha levels and the nature of change in serum sICAM-1 levels or serum sE-selectin levels, though serum TNF-alpha levels did not correlate with serum sICAM-1 levels or serum sE-selectin levels. These results suggest that higher levels of sICAM-1 and sE-selectin during asthma attacks may reflect the up-regulation of ICAM-1 and E-selectin expression in allergic inflammation, and that the soluble form of these adhesion molecules may be useful markers for the presence of allergic inflammation. TNF-alpha is shown to enhance the expression and release of ICAM-1 and E-selectin in vitro, however; the regulatory mechanism in the elevation of serum sICAM-1 and sE-selectin levels remains to be clarified.

Acute Disease↗
PubMed1994

Effect of cytokines on mediator release from human dispersed lung mast cells.

To evaluate the contribution of human lung mast cells (HLMC) to allergic inflammation, we investigated whether or not cytokines, including stem-cell factor (SCF), monocyte chemotactic and activating factor (MCAF), and RANTES, activate HLMC. SCF induced histamine release from dispersed HLMC in a dose-dependent fashion (P < 0.01). The release was 7.8 +/- 1.0% at 500 ng/ml SCF (n = 9). This response was also observed in chopped lung tissue. HLMC from which surface IgE molecules had been removed by treatment with lactic acid responded to SCF, while these cells lost their response to anti-IgE. The process was relatively rapid and reached a maximum in 5 min. This response required extracellular calcium, and it was observed at 37 degrees C, but not at 4 degrees C or 20 degrees. A brief preincubation (10 min) with lower concentrations of SCF, which were ineffective in releasing histamine, enhanced anti-IgE-induced histamine release (P < 0.05), while its enhancing effect was lost by the longer preincubation (30 min). SCF did not prime basophils to enhance stimulated-histamine release. Interleukin (IL)-1 alpha, IL-1 beta, IL-3, IL-4, IL-5, granulocyte/macrophage-colony stimulating factor (GM-CSF), MCAF, and RANTES neither induced histamine release nor enhanced the release stimulated by anti-IgE after a 10- or 30-min preincubation. The combination of IL-3 and IL-4 showed no effect on histamine release from HLMC. Leukotriene (LT)C4/D4/E4 production by SCF was negligible, as compared with anti-IgE-induced LT production.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines↗
PubMed1994

Dexamethasone inhibits basophil migration.

Glucocorticoids have been shown to inhibit the local accumulation of basophils during the allergen-induced late-phase reaction (LPR). Since migration is an essential step in the recruitment of basophils from the circulation, we examined whether the widely used glucocorticoid, dexamethasone (DEX), directly acts on basophils to inhibit the migration caused by C5a, interleukin (IL)-3, and IL-8. When purified basophils were preincubated with various concentrations of DEX, a dose-dependent inhibition was observed; DEX at concentrations as low as 1 nM reduced the number of migrated basophils by 30-40%; at higher concentrations, it showed a slightly stronger inhibitory effect. There was no significant difference in the effect of DEX on the migration caused by the three chemoattractants. The action of DEX took place rapidly; apparent inhibition was observed even when migration was initiated without preincubation. Although the inhibitory effect of this agent was not reversed when DEX was removed by washing, the inhibition was not mediated by the toxicity as measured by the trypan-blue exclusion test. These results indicate that the in vivo blocking effect of glucocorticoids on basophil accumulation during LPR is mediated in part by direct action to inhibit the migration of basophils.

Basophils↗
PubMed1994

[Biological characters of enterohemorrhagic Escherichia coli isolates from diarrhea patients in Saitama (1990-1992)].

A total of 16 strains of Enterohemorrhagic Escherichia coli (EHEC) isolated from diarrea patients in Saitama from 1990 to 1992 were tested for their serotype, verotoxin production, biochemical characteristics, antibiotics sensitivity and plasmid profiles. By serotype analysis, 14 strains from two outbreaks and 12 sporadic cases were classified as type O157:H7, one as O111:H-(not motility) and one as O128:H2. Typing of verotoxin by gene analysis using Polymerase Chain Reaction (PCR) showed that 9 of O157:H7 strains including two cases from outbreaks and O128:H2 have VT1 and VT2 genes, other O157:H7 have the VT2 gene and O111:H-has only the VT1 gene. Biochemical characteristic analysis indicated two strains of O157:H7 type from outbreaks were biotype II and the rest of O157:H7 were biotype I. One of the O157:H7 strain from a sporadic case showed positive for urease production. According to sensitivity tests against antibiotics, out of the O157:H7 group, one strain was resistant against ABPC, one against SM and two strains resistant to SM-TC. For plasmid profiles, all strains had 94 Kb plasmids and several smaller sizes of plasmids. But 5 strains of O157:H7 had 94 Kb plasmid only.

Bacterial Toxins↗