Biomedical subjects

K Yamazaki

Publications and source records attributed to K Yamazaki.

At least 19 recordsLinked to original sources

PubMed1992

Determination of eperisone in human plasma by gas chromatography-mass spectrometry.

A gas chromatographic-mass spectrometric method was developed to determine eperisone hydrochloride, 4'-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride, in human plasma over the concentration range 0.2-40 ng/ml. Excellent sensitivity was achieved by selection of a favorable fragment ion, m/z 98, of eperisone and reduction of heat decomposition of eperisone by using a splitless injector and a shortened capillary column. The method described here allows the determination of plasma concentrations as low as 0.2 ng/ml, the concentration attained 6 h after a single oral administration of 50 mg. At eperisone hydrochloride concentrations higher than 0.5 ng/ml, the mean inter-day variation of accuracy of the assay was less than 12%.

Calibration↗

PubMed1992

Changes in fatty acid composition in rat blood and organs after infusion of eicosapentaenoic acid ethyl ester.

An infusible emulsion of 10% eicosapentaenoic acid ethyl ester (EPA-EE, 99.2% pure) was prepared. Three ml of the emulsion was infused into tail veins of 20 Wistar rats weighing approx. 300 g. They were killed 1 h, 6 h, 24 h, 3 d and 7 d after the infusion, and fatty acid composition of various organs and plasma was analyzed along with that of control rats. There was no lipidosis in any organs of any rats. It was estimated that not less than 98% of infused EPA was cleared from plasma during the first hour after the infusion. EPA concentrations reached their peaks within 6 h after EPA infusion in plasma lipid fractions and in the phospholipid fraction of liver, heart, lung, kidney and spleen. The fatty acid composition of the phospholipid fraction of heart was very stable, and was not altered by EPA infusion except for a very slight increase in EPA at 1 h after the infusion (0.18% at 0 h to 0.56%). However, EPA concentrations increased markedly in the free fatty acid fraction of heart at 1 h after the infusion (0.15% at 0 h to 4.23%). Arachidonic acid concentrations decreased significantly within 24 h in the phospholipid fraction of organs except for heart. EPA emulsion might be useful for patients in whom a rapid increment in EPA in tissues is beneficial.

Animals↗

PubMed1992

Isolation and structural characterization of a new crosslinking amino acid, cyclopentenosine, from the acid hydrolysate of elastin.

A novel polyfunctional crosslinking amino acid, which was developed slower than lysinonorleucine and faster than desmosine on thin layer chromatography, was isolated from the hydrolysate of bovine aorta elastin. Its proposed structure was verified by ultraviolet spectroscopy, fast atom bombardment mass spectroscopy, and nuclear magnetic resonance spectroscopy. The data indicated it to be a trifunctional amino acid with a cyclopentene structure. The mass spectral analysis indicated a parent compound with a mass of 381 (C18H27N3O6). The proposed structure is one derived from the condensation of three allysine residues. Based on the names of other crosslinking amino acids found in elastin, the trivial name of cyclopentenosine is given to this compound.

Amino Acids↗

PubMed1992

Expression of urinary H-2 odortypes by infant mice.

The extended H-2 complex of genes in the mouse includes at least three loci that independently specify distinctive body odors, "odortypes," whose differential recognition influences mating choice and affects the maintenance of early pregnancy. A prime experimental method of identifying H-2 odortypes is the specially designed Y-maze in which mice are trained, by water deprivation and reward, to distinguish odors conducted to the arms of the maze from H-2-dissimilar mice or their urines. It is confirmed that H-2-dissimilar infant mice, unlike adult mice, are not distinguished by trained mice in the Y-maze. However, a previous conclusion that infant mice do not express H-2 odortypes is shown to be incorrect, because the urines of H-2-dissimilar infant mice, even at 1 day of age, were distinguished in the Y-maze. Thus urine, ingested by the mother, clearly could suffice for her to distinguish her own from other H-2-dissimilar pups. Further, urine would seem to be a unique source of H-2 odortypes. If, as we believe, H-2 odortypes represent mostly compound odors composed by H-2 genetic variation in the urinary output of odorous metabolites, as distinct from simple odors that depend on chemical differences of single odorants, then the kidney, which is not responsible for H-2 odortype specificity, may nevertheless impart a unique character to urinary odortypes by virtue of differential excretion/resorption processing of various constituent odorous metabolites. In that case, various organs and tissues, among which the hematopoietic/lymphoid system is known to contribute to H-2 odortype specificity, may exhibit tissue-specific varieties of H-2 odortypes, their products having not yet been subjected to renal processing.

Age Factors↗

PubMed1992

Comparison of the conversion rates of alpha-linolenic acid (18:3(n - 3)) and stearidonic acid (18:4(n - 3)) to longer polyunsaturated fatty acids in rats.

The delta 6-desaturase reaction is regarded to be the rate-limiting step in the conversion of linoleic acid (18:2(n - 6)) to arachidonic acid (20:4(n - 6)). The same is probably also the case with the conversion of alpha-linolenic acid (18:3(n - 3)) to eicosapentaenoic acid (20:5(n - 3)). However, there are very few in vivo studies that directly compared the conversion rate between 18:3(n - 3) and stearidonic acid (18:4(n - 3)), which is the delta 6-desaturated product of 18:3(n - 3). We compared this rate by feeding rats on a lipid-free diet supplemented with lard (9%, w/w) and 18:3(n - 3) ethyl ester (1%) diet or on a diet containing lard (9%) and 18:4(n - 3) ethyl ester (1%). A lard (10%)-supplemented diet was used as the control diet. The fatty acid compositions of total phospholipids, triglycerides and free fatty acids of both liver and plasma were measured after 1 or 3 weeks on different diets. The molar ratio of 20:5(n - 3) of most lipid fractions was about 2-fold higher in rats fed the 18:4(n - 3)-supplemented diet than in rats fed the 18:3(n - 3)-supplemented diet. 18:4(n - 3) was found in the liver lipid fraction in only a very small amount, even in the 18:4(n - 3)-supplemented groups. Thus, desaturation at C-6 is suggested to be the rate-limiting step in the conversion of 18:3(n - 3) to 20:5(n - 3).

Animals↗

PubMed1992

Acute and subacute inhalation toxicity of silane 1000 ppm in mice.

Male ICR mice were exposed to silane 1000 ppm, a concentration 200 or 2000 times higher than the recommended occupational exposure limits by many countries and academic associations, for 1, 2, 4, and 8 h (phase I study) and for 6 h/day, 5 days/week, over 2 and 4 weeks (phase II study). Hematological and biochemical studies were performed, and the animals were examined for histopathological lesions of the cornea, nasal cavity, respiratory tract, lung, liver, kidney, spleen, pancreas, thymus, thyroid, bone marrow, salivary glands, esophagus, and testis. All mice in both studies survived until they were sacrificed. In the phase I study, no exposure-related changes were found as a result of the hematological, biochemical, or histopathological examinations. In the phase II study, hematological and biochemical examinations failed to reveal any exposure-related changes, but mild irritation, manifested in the form of a small amount of exudate (eight out of ten animals), and inflammatory cells and/or necrotic cells on the nasal mucosa (six out of ten animals) was observed in the mice exposed to silane for 4 weeks. These findings suggest that silane toxicity and irritation are not severe.

Administration, Oral↗

PubMed1992

Assessing odor generalization in the rat: a sensitive technique.

In investigating the ability of the rat to discriminate among urine odors from mice of different genetic strains, we developed a technique for determining the extent of odor generalization. Trained rats performed a discrete trial, go/no-go procedure, touching a bar in the presence of an S+ odor for water reward. Rats easily learned this task and restricted their responding to trials with the S+ stimulus, even though there was no penalty for responding to S-. However, when presented with test stimuli that might be more similar to S+ or S-, some rats responded only to the S+, and not at all to S- or any generalization stimuli. We then created series of stimuli composed of different levels of adulteration of the S+ stimulus with generalization stimuli. With these stimuli, rats produced graded levels of responding, allowing comparisons of similarity among odorant stimuli. This technique can be applied to other types of odorant stimuli, particularly biological compounds of unknown concentration or purity, and should be of use in an operant laboratory studying odorant perception, or odorant characteristics.

Animals↗

PubMed1992

Neonatal lupus erythematosus in Japan.

BACKGROUND: Although more than 200 cases of neonatal lupus erythematosus (NLE) have been reported, the prognosis, clinical characteristics, and genetic background of the patients are still obscure. Their symptoms seem to vary in different races. OBJECTIVE: We had an opportunity to see two clinically different types of NLE. It is important to define the clinical characteristics in Japanese cases and to compare them to caucasian NLE cases reported earlier. METHODS: Sixty Japanese infants with NLE and their mothers reported in Japan were investigated and compared with cases reported from other countries. RESULTS: Japanese cases were highly associated with anti-SS-A/Ro, anti-SS-B/La, anti-ribonuclear protein, and anti-DNA antibodies. A low frequency of congenital heart block was noted but 8.3% of the cases progressed to systemic lupus erythematosus. HLA-DRw12 was a significantly relative risk in NLE. CONCLUSION: The clinical characteristics of Japanese NLE patients were different from those of caucasian patients reported in the literature.

Adult↗

PubMed1992

Effects of LP-805, a novel vasorelaxant agent, a potassium channel opener, on rat thoracic aorta.

1. In rat thoracic aorta, LP-805 (0.1-10 microM) caused the marked reduction of NE-induced maximum response and relaxed the low K+ (less than 35.9 mM)-induced contraction, in a concentration-dependent manner, but failed to relax the high K+ (65.9 mM)-induced contraction. 2. Glibenclamide (0.3-1 microM) caused a parallel shift of concentration-response curve produced by LP-805 for 25.9 mM K(+)-induced contraction and prevented the LP-805-induced reduction in maximum response evoked by NE in a concentration-dependent manner. 3. Glibenclamide (10 microM) prevented the LP-805 (10 microM)-induced decrease in cytosolic Ca2+ levels which was increased by 1 microM NE or 25.9 mM K+. 4. LP-805 (10 microM) increased basal 86Rb efflux, which was completely inhibited by 10 microM glibenclamide. 5. The results suggest that LP-805 causes a vasorelaxation as a consequence of the decrease in cytosolic Ca2+ levels due to the increase in K+ efflux via opening ATP-dependent K+ channels.

Animals↗

PubMed1992

Reduction of delayed-type hypersensitivity by the injection of n-3 polyunsaturated fatty acids in mice.

The effects of injection of n-3 polyunsaturated fatty acids (PUFAs) on the delayed-type hypersensitivity (DTH) response was investigated in mice. Mice were immunized with sheep red blood cells (SRBCs). Six days later 50 microliters of a 20% SRBC suspension was injected into the right hind footpad of each mouse. Just before the challenge of SRBCs, various amount of a trieicosapentaenoyl-glycerol emulsion (10%) was injected through tail veins (5 mice per each dose). Then 24 hr later the dorsoventral thickness of the right hind footpad was measured and compared with that of the left hind footpad. The difference in thickness between both footpads was regarded as the DTH response. The effect of the emulsion on DTH was dose-dependent; the DTH responses (in mm) in the control group (injected with 0.5 ml of a 2.5% glycerol solution through tail veins) and EPA-injected groups (with 5 mg, 10 mg, and 20 mg) were 1.53 +/- 0.16 (mean +/- SEM), 1.09 +/- 0.14, 0.43 +/- 0.07 (P less than 0.005), and 0.36 +/- 0.13 (P less than 0.005), respectively. The DTH response was also depressed by the injection of a tridocosahexaenoyl-glycerol emulsion. Consequently, n-3 PUFA emulsions have clinical implication in DTH-related diseases such as rejection of allografts.

Animals↗

PubMed1992

Demonstration of low molecular weight polypeptides associated with small, round-structured viruses by western immunoblot analysis.

Small, round-structured viruses (SRSV) were detected in 14 of 300 fecal specimens obtained from patients with acute gastroenteritis by electron microscopy. These SRSV strains were morphologically indistinguishable from one another. While 11 of these strains had a single usual major structural protein with molecular weight of 63,000 (63K) daltons (p63), interestingly, three strains possessed a single major structural protein with molecular weight of 33K daltons (p33). Treatments of p63-SRSV with proteolytic enzymes or denaturating reagents did not affect the molecular weight of p63, and the p33 was not detectable by Western immunoblot in the ultracentrifugal supernatant of the p63-SRSV suspension. These results suggest that the p33 is neither a definitive subunit of p63 nor disintegrated component derived from the p63-SRSV but a novel polypeptide of SRSV. Immune electron microscopy and Western immunoblot analyses indicated that p63- and p33-SRSVs may share an antigenic determinant(s).

Acute Disease↗

PubMed1992

Dying back type axonal degeneration of sensory nerve terminals in muscle spindles of the gracile axonal dystrophy (GAD) mutant mouse.

A disorder of the gracile axonal dystrophy (GAD) mutant mouse is characterized by a neuromuscular disease with sensory ataxia (detectable 30 days after birth) and paresis of the hindlimbs (detectable at 80 days). In the sensory ataxia stage, histological study of the primary sensory system shows that, in addition to the lesions in the central nervous system, peripherally projecting axons have also started to degenerate at their distal ends in muscle spindles. Although the structure of Ia fibre endings appear normal until 15 days after birth, initial changes in the annulo-spiral structure are detected around the 20th day by a degeneration of the terminal axons. Degeneration then progressed proximally and the secondary endings also start to degenerate. Neuron cell bodies located in the dorsal root ganglia are morphologically intact until the later stages. Chronological studies indicate that, although axonal degeneration progresses throughout life, it is accentuated during the rapid somatic growth period. Around 50 days of age, transient regeneration takes place at axonal endings when somatic growth has attained a plateau. Such primary sensory endings tend to be restored by fine, multiple axons which gain access to the intrafusal fibres through the original endoneurial tubes. Ultrastructural observations at the fully affected stage show intrafusal muscle fibres lying scattered within spindles due to loss of the fine network of inner capsule layers and an almost complete loss of sensory endings from the surface of intrafusal muscle fibres. These results indicate that this mutant mouse is a useful model for naturally occurring 'dying back' type axonal degeneration or 'central and peripheral distal axonopathies', and would provide significant information about the complete evolution of the pathological processes involved.

Animals↗

PubMed1992

Direct and indirect effects of Porphyromonas gingivalis lipopolysaccharide on interleukin-6 production by human gingival fibroblasts.

We examined the production of interleukin-6 (IL-6) by human gingival fibroblasts (ATCC CRL 1292) stimulated with lipopolysaccharide (LPS) from Porphyromonas gingivalis and Escherichia coli, or supernatant of human peripheral blood adherent cell culture medium incubated in the presence of IL-1 and the same two LPS. Confluent monolayers of gingival fibroblasts were incubated with stimulants for 6 h at 37 degrees C in 5% CO2 and air. After removal of stimulants, the cell cultures were incubated for an additional 2 or 24 h in the same environment. At the end of the culture period, supernatants were collected and assayed for IL-6 activity by stimulatory IgG production with the human B-lymphoblastoid cell line CESS. The direct effect of LPS on IL-6 production by gingival fibroblasts was much weaker than the indirect one via IL-1 production by adherent cells. The stimulating effect of culture supernatants of adherent cells stimulated with LPS on IL-6 production by gingival fibroblasts was as effective as that of recombinant IL-1, when this latter was added at a concentration equivalent to that contained in the culture supernatant of adherent cells. These results suggest that, although gingival fibroblasts may be involved in the pathogenesis of chronic periodontal disease by the production of cytokines, such a role may not result from a direct stimulation by periodontopathic bacteria. The phenomenon is more likely to be mediated indirectly by IL-1 produced by infiltrating inflammatory cells.

Analysis of Variance↗

PubMed1992

[Pneumonia caused by Moraxella subgenus Moraxella sp].

Moraxella subgenus Moraxella sp. was isolated in pure culture from the sputum of a 43-year-old male with pneumonia and congestive heart failure due to idiopathic dilated cardiomyopathy. In this case, we concluded that the patient's bacterial pneumonia was caused by M. (M.) sp. based on a Gram stain of the sputum smear and bacterial findings, increased WBC count, and elevated CRP. A chest X-ray revealed right middle, and left upper and middle lobe infiltrates. This Moraxella strain produced a BRO-type beta-lactamase, a carbenicillinase-type enzyme.

Adult↗

PubMed1992

Intravenous infusion of trieicosapentaenoyl-glycerol and LTB4 and LTB5 production by leukocytes of rabbits.

During myocardial infarction leukotriene B4 (LTB4) is probably a major determining factor of tissue damage because it can amplify the inflammatory reaction by recruiting leukocytes and degranulating them. Oral administration of eicosapentaenoic acid (EPA) is known to reduce LTB4 production by polymorphonuclear leukocytes (PMNL). However, it takes several weeks for EPA to take effect. In this study, we formulated a trieicosapentaenoyl-glycerol emulsion and infused it into rabbits (0.8 g EPA/kg). In the ex vivo study, the inhibition of LTB4 production by PMNL from EPA-infused rabbits was maximal (32-60% of preinfusion values, P less than 0.01) 6 h after the infusion. There was also a tendency toward reduced LTB4 production 1, 24, and 168 h after the infusion. A lower dose (0.2 g EPA/kg) also reduced LTB4 production (45% of preinfusion values, P less than 0.02) 6 h after the infusion. There was no significant change in LTB4 production in control groups in which soybean oil emulsion was infused instead of EPA. EPA infusion might be useful for reduction of tissue damage in the acute phase of LTB4-related diseases such as acute myocardial infarction.

Animals↗

PubMed1992

Tumor size of renal cell carcinoma: its clinical implication.

We studied the clinical implication of tumor size in renal cell carcinoma, by revealing its relation with the other histopathological and clinical features. The tumor size was well correlated with histopathological findings and metastatic status of the carcinoma. Smaller carcinomas (usually less than 60 mm) generally had a higher disease-specific survival than those of 60 mm or greater. The results indicated that the size reflected the biological character of the carcinoma. However, 10% of patients with the smaller carcinoma had lymph node metastasis or distant metastasis at the time of diagnosis, each of which contributed to a renal cell carcinoma-related death in the early follow-up period.

Carcinoma, Renal Cell↗

PubMed1992

Parental methylation patterns of a transgenic locus in adult somatic tissues are imprinted during gametogenesis.

The methylation status of a mouse metallothionein-I/human transthyretin fusion gene was studied during gametogenesis in transgenic mice. In the adult tissues of this mouse line, the promoter region of the transgene on chromosome 11 is methylated when it is maternally inherited and undermethylated when it is paternally inherited. Germ cells from various developmental stages of gametogenesis were isolated, and their DNAs were assayed using methylation-sensitive restriction endonucleases and the polymerase chain reaction. Only low to nonexistent levels of transgene methylation were detected in germ cells from 14.5-day-old male and female fetuses irrespective of the parental origin of the transgene. This undermethylated state persisted in oocytes from newborn females as well as in testicular spermatogenic cells and sperm. By contrast, the transgene promoter was completely methylated in fully grown oocytes arrested at the first meiotic prophase. The endogenous metallothionein-I gene promoter, located on a different chromosome, remained undermethylated at all stages examined, consistent with previous findings reported for a typical CpG island. Taken together, the results suggest that parental-specific adult patterns of transgene methylation are established during gametogenesis.

Animals↗

PubMed1992

Behavioral study on the gracile axonal dystrophy (GAD) mutant mouse.

We investigated motor function and pain sensation in the gracile axonal dystrophy (GAD) mutant mouse, using the tail-flick test and the rotarod test. GAD (gad/gad) and normal sib mice (gad/+ or +/+) were used between 5 and 11 weeks of age, during which time the behavioral signs of GAD mice shifted from sensory ataxia (about 4 to 8 weeks of age) to paresis (after about 9 weeks of age). In the tail-flick test, significant shortening of latency was observed at 6 and 8 weeks of age in female GAD mice, in comparison with normal female mice. This may be related to dysfunction or degeneration of axons in the fasiculus gracilis, whose collaterals are thought to control the transmission of nociceptive information. In the rotarod test, a cumulative chi 2 test showed significant reduction in the performance times of GAD mice beginning at 5 and 6 weeks of age in males and females, respectively, indicating that the rotarod test can detect the development of motor incoordination as early as these ages. The performance times of GAD mice dropped sharply from 9 weeks of age onwards, and this is believed to reflect the progression of paresis. The rotarod test therefore appears to be a good method of quantifying behavioral changes in GAD mice and to be applicable both to objective selection of GAD mice before 8 weeks of age and to evaluation of drugs to treat ataxia or paresis.

Age Factors↗