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Biomedical subjects

K Saeki

Publications and source records attributed to K Saeki.

At least 217 records · Page 12Linked to original sources
PubMed1992

Effects of standard cigarette smoke and nicotine-reduced cigarette smoke on plasma concentrations of indomethacin administered orally to rats.

The influence of acute exposures to standard (ST) and nicotine-reduced (NR) cigarette smokes on the plasma concentration of orally administered indomethacin (IM, 5 mg/kg) was investigated in rats. IM plasma concentrations in the ST- and NR-groups were lower than those in the non-smoking control group, while the lowered effect in the NR-group was slightly weaker than in the ST-group. These results suggest that the plasma concentrations of IM administered orally are lowered by the acute exposure of cigarette smoke, and this influence may be attributed largely to constituents other than nicotine in the cigarette smoke as well as slightly attributable to nicotine.

Administration, Oral↗
PubMed1992

In vivo and in vitro release of indomethacin from water-soluble and fatty base suppositories.

The plasma concentration of indomethacin was measured after the rectal administration of water-soluble and fatty base suppositories in rats. The results were compared with the in vitro indomethacin release from suppositories determined by Paddle method using three different types of membranes: cellulose membrane, artificial sausage membrane and natural sausage membrane. The plasma concentrations of indomethacin during the first 4h after the rectal administration were higher in rats that received water-soluble base suppositories than in those that received fatty base types. When either a cellulose membrane or an artificial sausage membrane of cow protein was used in the Paddle method, the amount of indomethacin released from fatty base suppositories was significantly higher than that from water-soluble base ones. However, the results were reversed when a natural sausage membrane of pig colon was used. The discrepancy in the in vitro experiments using water-soluble base suppositories seemed to be due to the difference of pore size of membrane used. Careful consideration should be given to the membrane used in the Paddle method especially when this method is employed to examine the release of poorly soluble drugs like indomethacin in both water-soluble and fatty base suppositories.

Animals↗
PubMed1992

Selective inhibitory effects of calcium channel antagonists on the two components of the neurogenic response of guinea pig vas deferens.

The effects of L-type calcium channel antagonists and omega-conotoxin on the contractile responses of guinea pig vas deferens were examined in vitro. Electrical stimulation of the postganglionic hypogastric nerve induced biphasic contraction consisting of rapid phasic and delayed tonic components. L-type calcium channel antagonists, such as diltiazem, verapamil and nicardipine, mainly inhibited the delayed tonic component, whereas omega-conotoxin mainly inhibited the rapid phasic component. Stimulations in the presence of prazosin and alpha, beta-methylene ATP induced rapid transient and delayed contraction, respectively, which were inhibited by omega-conotoxin and L-type calcium channel antagonists, respectively. Short-term stimulation with five pulses induced a small fast phasic contraction. This contraction, which could be desensitized by alpha, beta-methylene ATP, was inhibited by omega-conotoxin, but not by L-type calcium channel antagonists. At the concentrations used in the present study, none of the calcium channel antagonists inhibited the contractions induced by exogenously added ATP or norepinephrine. These findings suggest that L-type calcium channel antagonists and omega-conotoxin inhibit the neurotransmissions mediated by norepinephrine and ATP, respectively, from the postganglionic nerve to the vas deferens of the guinea pig. Inhibition of the voltage-dependent calcium channel is discussed in relation to the mechanism of cotransmission in this preparation.

Adenosine Triphosphate↗
PubMed1992

A case of endogenous Enterococcus faecalis endophthalmitis.

A case of successful treatment by vitrectomy and lensectomy of early-stage endogenous endophthalmitis caused by Enterococcus faecalis was reported. The case was a 50-year-old man with poorly controlled diabetes. Following T-tube drainage for a necrotic cholecystitis operation, he developed iridocyclitis in both eyes as well as fever. At the time of his first visit to our clinic, his right eye had already lost light perception. His left eye had visual acuity recognizing hand movement, marked uveitis, complicated cataract, and dense vitreous opacity. As gram-positive cocci were isolated from the aspirated vitreous, lensectomy and vitrectomy under irrigation with antibiotics were conducted. After the administration of systemic postoperative antibiotics and human immunoglobulin, the patient showed remarkable improvement in the state of his ocular fundus. By 60 days after the surgery, the visual acuity of his left eye recovered to 0.2. Endogenous Enterococcus faecalis endophthalmitis has rarely been reported in Japan. The diagnosis and treatment of this disease with reference to the above findings were discussed.

Cataract Extraction↗
PubMed1991

Transcriptional analysis of two Rhodobacter capsulatus ferredoxins by translational fusion to Escherichia coli lacZ.

Plasmids which contained the translational fusion of Escherichia coli lacZ to Rhodobacter capsulatus ferredoxin genes, fdxN and fdxA, were constructed. Effects of growth conditions on the expression of each ferredoxin were analyzed by measuring the beta-galactosidase activity in R. capsulatus which harbored a corresponding plasmid. Transcription of fdxN::lacZ, the ferredoxin I fusion gene, was regulated at least 100-fold by either NH4+ or O2 but not by illumination, confirming that fdxN belongs to the nif-gene family. Transcription of fdxA::lacZ, the ferredoxin II fusion gene, however, was constant under all the conditions surveyed, suggesting that the protein has some constitutive function(s).

Escherichia coli↗
PubMed1991

Isolation of human salivary polymorphonuclear leukocytes and their stimulation-coupled responses.

A simple method was developed to isolate viable human salivary polymorphonuclear leukocytes (SPMN) from the oral cavity, and stimulation-coupled responses of these cells were examined. From morphological characteristics and the presence of neutrophil-specific annexin protein (39-kDa protein), we found that these cells seemed to be very similar to human peripheral polymorphonuclear leukocytes (PPMN), although they were in rather young stages. Stimulation-coupled responses of these cells were observed in terms of superoxide (O2.-) genration, luminol chemiluminescence response (LCL), membrane depolarization, and changes in intracellular calcium ion concentration ([Ca2+]i). The rates of superoxide generation by various stimuli, such as formylmethionylleucylphenylalanine (FMLP), phorbol 12-myristate 13-acetate (PMA) and opsonized zymosan (OZ) were different. Superoxide generation and strong chemiluminescence response were observed without addition of any stimuli. This endogenous LCL was inhibited by azide and superoxide dismutase (SOD), but not by uric acid (UA). The intensity of the endogenous LCL decreased with time after isolation from the oral cavity. This decrease was accompanied by the appearance of a FMLP-coupled response. Furthermore, the endogenous activity which produced active oxygen species was maintained in the medium at 4 degrees C for a long period after isolation. From these results, it is suggested that SPMN have the ability to show characteristic responses to various stimuli, and that SPMN play important roles in the defense mechanisms in the oral cavity.

Annexins↗
PubMed1991

Genetic analysis of functional differences among distinct ferredoxins in Rhodobacter capsulatus.

Rhodobacter capsulatus has been known to possess two ferredoxins (I and II) with distinct physicochemical and structural properties: ferredoxin I is a 2[4Fe-4S] type and the other is a [3Fe-4S] [4Fe-4S] type. To analyze their possible functional differences, their genes (fdxN and fdxA) were cloned, sequenced, and subjected to interposon mutagenesis experiments. The former gene was adjacent to a gene encoding a chloroplast-type [2Fe-2S] ferredoxin (fdxC). Mutants with inactivated fdxN and/or fdxC were obtained, and they showed virtually no growth under nitrogen-fixing conditions. Complementation experiments confirmed that both fdxN and fdxC were required for nitrogen fixation. On the other hand, we have not been able to disrupt fdxA under the screening conditions surveyed, including conditions that do not require nitrogenase activity for growth, suggesting that ferredoxin II could have an unknown essential role(s). These indicate functional differences among multiple ferredoxins in one bacterium other than in cyanobacterial heterocysts and indispensability of certain ferredoxins in nitrogen fixation other than Rhizobium meliloti FdxN.

Amino Acid Sequence↗
PubMed1991

Feeding-induced increase in the extracellular concentration of histamine in rat hypothalamus as measured by in vivo microdialysis.

The extracellular concentration of histamine (HA) in the hypothalamus of conscious and freely moving rats was measured by in vivo microdialysis and the effects of fasting and feeding on the HA concentration were examined. In non-fasted rats, the basal HA concentration was almost constant from 11.00 to 17.00 h on the day following implantation of the dialysis probe, the mean value being 11.1 pg/30 min. No significant change in the HA concentration was observed in rats deprived of food for 24 h. In 24-h fasted rats, feeding for 15 min produced a transient and significant increase in the HA concentration. These results suggest that histaminergic activity in the rat hypothalamus increases during feeding.

Animals↗
PubMed1991

Histiocytic neoplasias: immunohistochemical evaluation of their frequencies among malignant lymphoma and related conditions in Japan.

Through histologic review of 1,766 cases with malignant lymphoma and related conditions, 35 cases (2%) were selected as probable histiocytic neoplasias. Proliferating cells in these cases had voluminous, granulated cytoplasm, and round to irregularly shaped nuclei often with bi- or multinucleated forms showing monomorphous or polymorphous proliferation accompanying small lymphocytes, plasma cells, and, less frequently, eosinophils. Cases showing proliferation of convoluted cells with numerous benign-appearing histiocytes or large cells with clear cytoplasm were excluded under a diagnosis of T-cell lymphoma. To evaluate the immunologic character of proliferating cells, immunohistochemistry using antibodies Mx-Pan B, MB-1, MT-1, UCHL-1, lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S-100 alpha, S-100 beta, Leu M1, epithelial membrane antigen, and Ki-1 were carried out in 23 cases. Naphthol-ASD-chloracetate reaction and toluidine blue stain were also performed. These procedures revealed that 12 cases (52%) were B-cell type, three cases (13%) T-cell type, six cases (26%) true histiocytic type, and two cases null type. Therefore, the frequency of cases with true histiocytic neoplasias among cases with malignant lymphoma and related conditions in Japan may be 0.5%.

Antibodies, Monoclonal↗
PubMed1991

In vivo effects of some histamine H1-receptor antagonists on monoamine metabolism in the mouse brain.

The in vivo effects of four H1-antagonists, diphenhydramine, chlorpheniramine, mepyramine, and promethazine, on the metabolism of noradrenaline (NA), dopamine (DA), and 5-hydroxytryptamine (5-HT) were investigated in the whole mouse brain. Diphenhydramine and chlorpheniramine had no significant effect on levels of NA, 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), DA, and 5-HT, but they significantly decreased levels of 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA). In particular chlorpheniramine markedly decreased 5-HIAA levels at doses as low as 1 mg/kg, i.p. Mepyramine significantly decreased 5-HIAA levels but not those of other substances. High doses of promethazine significantly decreased NA levels but markedly increased those of MHPG, DOPAC, HVA, 5-HT, and 5-HIAA. The DA reduction induced by alpha-methyl-p-tyrosine (alpha-MT) was significantly inhibited by diphenhydramine, chlorpheniramine, and promethazine, but the alpha-MT-induced NA decrease was significantly enhanced by promethazine. The 5-HIAA accumulations induced by probenecid were significantly inhibited by chlorpheniramine and mepyramine. These results suggest: (1) Diphenhydramine and chlorpheniramine inhibit the turnover of both DA and 5-HT by blocking their neuronal uptake. (2) Promethazine and mepyramine inhibit DA and 5-HT turnover, respectively, as a result of the inhibition of the uptake mechanism. (3) Promethazine increases NA turnover by enhancing NA release. The discriminative effects of these drugs on the monoamine systems may be related to some differences in their CNS actions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Prostaglandin E2 selectively affects purinergic transmission in guinea pig vas deferens.

The effect of prostaglandin E2 (PGE2) on the contractile response of the guinea pig vas deferens was examined. Postganglionic hypogastric nerve stimulation for 7 sec at 20 Hz induced a biphasic contractile response, consisting of fast phasic and delayed tonic components. Prostaglandin E2 delayed the onset and increased the maximum contractile responses. Stimulation in the presence of prazosin induced only a fast phasic contraction. Treatment with PGE2, in the presence of prazosin, delayed the onset of this response and increased its maximum. The delayed contraction, observed on stimulation in the presence of alpha,beta-methylene adenosine triphosphate (ATP), was enhanced moderately and concentration-dependently by PGE2. Short-term stimulation with 5 pulses induced a small fast phasic contraction. This contraction, which could be desensitized by alpha,beta-methylene ATP, was inhibited by PGE2 but not by prazosin. Prostaglandin E2 significantly enhanced the transient phasic contraction, induced by addition of exogenous ATP to the organ bath and had a similar but somewhat smaller effect on the tonic contraction induced by the addition of exogenous norepinephrine (NE). These findings suggest that PGE2 selectively delayed neurotransmission, mediated by ATP and enhanced contractions of the smooth muscle of guinea pig vas deferens, elicited by ATP or NE.

Adenosine Triphosphate↗
PubMed1991

Early morphological events of in vitro fertilized bovine oocytes with frozen-thawed spermatozoa.

Bovine follicular oocytes were matured and inseminated in vitro with spermatozoa capacitated in vitro. The first evidence of sperm penetration was observed at 3 h after insemination. The penetration rate increased until 5 h, and reached a maximum rate (92%) at 5 h. Decondensation of the sperm head and pronuclear formation were observed 4 h and 7 h after insemination, respectively. Female chromatins of all penetrated oocytes were activated at 3 h, and female pronuclei were formed at 7 h after insemination. Percentages of oocytes with male and female pronuclei at 9 h were 88 and 94%. Polyspermy (4, 7, 19 and 29% at 4, 5, 7 and 9 h after insemination, respectively) and abnormal development of male pronuclei (6 and 7% at 7 and 9 h after insemination, respectively) were also seen.

Journal Article↗
PubMed1991

Quantitative indices of dispersion of refractoriness for identification of propensity to re-entrant ventricular tachycardia in a canine model of myocardial infarction.

STUDY OBJECTIVE: To identify propensity to re-entry in a canine model of 7 day old myocardial infarction, the sensitivity and specificity of five indices of dispersion of refractoriness (ERP) were investigated. DESIGN: With an epicardial patch electrode containing 47 electrodes, ERP was measured by S1-S2 method at each site overlying the infarct. ERP range, maximum adjacent dispersion, difference between mean ERPS of the infarct and normal zones, standard deviation (sigma) of the mean ERP, and sigma/mean ERP X 100 were calculated. EXPERIMENTAL MATERIAL: 42 dogs were divided into three groups; 20 dogs with epicardial functional block on induction of sustained ventricular tachycardia or fibrillation, 10 dogs with inducible ventricular tachycardia or fibrillation but without epicardial functional block, and 12 control dogs without ventricular tachycardia, fibrillation or block. MEASUREMENTS AND MAIN RESULTS: All five indices were significantly greater in the 20 dogs with ventricular tachycardia or fibrillation than in control dogs. A receiver operating characteristic curve analysis of the five indices showed that sigma was the most sensitive and specific index for discriminating these 20 dogs. The sensitivity and specificity of a sigma value greater than 14 ms (the mean value plus two SD of the control dogs) were 70% and 100%, respectively.

Animals↗
PubMed1991

In vitro fertilization and development of bovine oocytes matured in serum-free medium.

This study was undertaken to investigate the effects of supplementation of serum (fetal calf serum), gonadotropins (LH, FSH, prolactin) and estradiol-17 beta (E2) to culture medium during in vitro maturation of bovine cumulus oocyte complexes on subsequent fertilization and development to the blastocyst stage in vitro. Serum supplementation during bovine oocyte maturation was not required but hormonal supplementation, gonadotropins (LH + FSH) and E2, enhanced the fertilizability and developmental ability of bovine oocytes matured in vitro. The addition of prolactin to maturation medium containing LH, FSH, and E2 did not further enhance frequencies of fertilization and development.

Animals↗
PubMed1991

Cardiac tamponade due to rupture of a subepicardial aneurysm following myocardial infarction.

A 71-year-old male died of cardiac tamponade due to cardiac rupture 22 days after onset of acute myocardial infarction. Autopsy revealed rupture of an unusual ventricular aneurysm characterized by abrupt interruption of the myocardium, a narrow neck, a thin fibrous outer wall partially showing myocardial fibers, and lack of adhesion between the epicardium and pericardium. A review of the literature revealed that 11 among 32 autopsy cases of false aneurysm showed a similar morphology to the present case, these being classifiable as subepicardial aneurysm.

Aged↗
PubMed1991

Characterization of histamine release from the rat hypothalamus as measured by in vivo microdialysis.

The release of endogenous histamine (HA) from the hypothalamus of anesthetized rats was measured by in vivo microdialysis coupled with HPLC with fluorescence detection. Freshly prepared Ringer's solution was perfused at a rate of 1 microliter/min immediately after insertion of a dialysis probe into the medial hypothalamus, and brain perfusates were collected every 30 min into microtubes containing 0.2 M perchloric acid. The basal HA output was almost constant between 30 min and 7 h after the start of perfusion, with the mean value being 7.1 pg/30 min. Thus, the extracellular HA concentration was assumed to be 7.8 nM, by a calculation from in vitro recovery through the dialysis membrane. Perfusion with a high K+ (100 mM)-containing medium increased the HA output by 170% in the presence of Ca2+. Systemic administration of either thioperamide (5 mg/kg, i.p.), a selective H3 receptor antagonist, or metoprine (10 mg/kg, i.p.), an inhibitor of HA-N-methyltransferase, caused an approximately twofold increase in the HA output 30-60 min after treatment. The combined treatment with thioperamide and metoprine produced a marked increase (650%) in the HA output. The HA output decreased by approximately 70% 4-5 h after treatment with alpha-fluoromethylhistidine (alpha-FMH; 100 mg/kg, i.p.), an inhibitor of histidine decarboxylase. Furthermore, the effect of combined treatment with thioperamide and metoprine was no longer observed in alpha-FMH-treated rats. These results suggest that both HA-N-methyltransferase and H3 autoreceptors are involved in maintaining a constant level of extracellular HA and that their blockade effectively results in a higher activity level of the endogenous histaminergic system in the CNS.

Animals↗
PubMed1991

Changes in the metabolism of histamine and monoamines after occlusion of the middle cerebral artery in rats.

Changes in the levels of histamine, monoamines, and their metabolites in the cerebral cortex and striatum after occlusion of the middle cerebral artery in rats were examined. The water content of the ipsilateral brain regions gradually increased after occlusion. In the ischemic side, 1 h after occlusion, the cortical norepinephrine and striatal 5-hydroxy-tryptamine levels significantly decreased, and striatal 3,4-dihydroxyphenylacetic acid and homovanillic acid levels markedly increased. In contrast, the levels of histamine and tele-methylhistamine in either brain region gradually increased and the changes became pronounced and statistically significant 6-12 h after induction of ischemia. The striatal histamine and tele-methylhistamine reached levels three- and twofold higher, respectively, than those of the contralateral side. In rats treated with alpha-fluoromethylhistidine 1 h before induction of ischemia, elevation of histamine and tele-methylhistamine was not observed. The elevated histamine level in the ipsilateral straitum at 9 h after occlusion was further significantly increased by the treatment with metoprine, an inhibitor of histamine-N-methyltransferase. These results suggest that the histaminergic activity in the brain is gradually enhanced by cerebral ischemia.

Amines↗