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Biomedical subjects

K Seto

Publications and source records attributed to K Seto.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Does midazolam release histamine?].

Effects of induction with midazolam on serum histamine levels (Study 1) and the volume as well as pH of gastric juice (Study 2) were studied. Anesthesia was induced with midazolam 0.2 mg.kg-1 in midazolam group, thiamylal 4 mg.kg-1 in control group. In Study 1, serum histamine levels were measured with high performance liquid chromatography till 180 minutes after intubation. There were no statistical significance between the two groups in serum histamine levels at all points. But in midazolam group, at 30 minutes after intubation, the histamine level was significantly lower than the preinduction level. In control group, serum concentration of histamine increased but not significantly. In Study 2, gastric juice was sampled through naso-gastric tube inserted on the morning of operation. Gastric juice pH was measured with the use of pH Strip (E. Merck, F.R. Germany). There were no significant differences between the two groups in volume as well as pH of gastric juice at all points. It is concluded that midazolam used for induction of anesthesia might decrease histamine release, but it has no clinical effects on gastric juice secretion.

Adult↗
PubMed1990

[Does induction with midazolam decrease stress response during anesthesia?].

The effects of midazolam on stress response during surgery compared with thiamylal were studied. Twelve patients were divided into 2 groups at random; midazolam group and thiamylal group. Anesthesia was induced with midazolam 0.2 mg.kg-1 or thiamylal 4 mg.kg-1 in each group, and maintained with O2 2 l.min-1, N2O 4 l.min-1 and enflurane. The plasma concentration of catecholamine was measured at preinduction, 10, 30, 60, 120 and 180 minutes after intubation. No significant differences were seen between 2 groups in plasma concentration of catecholamine. In midazolam group, plasma concentration of epinephrine decreased significantly 10 minutes after intubation as compared with preinduction level. The plasma concentration of norepinephrine in midazolam group tended to decrease. In thiamylal group, plasma concentration of norepinephrine tended to increase and increased significantly at 120 and 180 minutes after intubation as compared with preinduction level. These results suggest that induction with midazolam suppresses stress response during anesthetic induction and surgery more intensely than induction with thiamylal.

Adult↗
PubMed1990

[Total intravenous anesthesia with continuous infusion of midazolam].

Continuous infusion of midazolam and fentanyl were used in total intravenous anesthesia. Anesthesia was induced with midazolam 0.3 mg.kg-1 in 100% O2. Tracheal intubation was facilitated with succinylcholine 1 mg.kg-1 after precurarization with pancuronium 1 mg. The infusion regimen of midazolam was as follows; an initial infusion of 0.68 mg.kg-1.hr-1 for 15 min followed by a maintenance infusion of 0.125 mg.kg-1.hr-1, and about 30 min before the end of operation infusion was stopped. Fentanyl and pancuronium were injected as required. During operation, blood pressure and heart rate were stable with a small dose of nicardipine. Total dose of fentanyl was the same as in NLA. Extubation was done as quickly as in NLA, after aminophylline infusion which was said to reverse midazolam. In the recovery room, patients were asleep and snored. But they opened eyes and responded to verbal command. Respiratory rate and PaCO2 were in normal ranges. Total intravenous anesthesia was possible with midazolam and fentanyl but a further study is necessary.

Adult↗
PubMed1990

[Total intravenous anesthesia with continuous infusion of midazolam--study on plasma levels of midazolam and catecholamines].

Total intravenous anesthesia was performed with continuous infusion of midazolam and bolus injection of fentanyl. A bolus injection of midazolam 0.3 mg.kg-1 was followed by an infusion regimen with an initial infusion rate of 0.68 mg.kg-1.hr-1 for 15 min followed by a maintenance infusion of 0.125 mg.kg-1.hr-1 and infusion was stopped at about 30 min before the end of operation. Fentanyl and pancuronium were injected as required. Nicardipine was given for intraoperative hypertension. Plasma concentrations of epinephrine and norepinephrine decreased significantly at 10 min after induction, but increased significantly during operation. Therefore, this anesthetic method was considered not to be so deep. Plasma concentrations of midazolam were higher than 200 ng.ml-1 during operation. After discontinuation of midazolam infusion, its concentration decreased quickly, and the elimination half life of midazolam was 1.675 +/- 0.2807 hr. The value was not so large as we had anticipated. Total intravenous anesthesia with continuous infusion of midazolam and bolus injection of fentanyl is thought to produce light anesthesia. Plasma concentration of midazolam decreased quickly.

Adult↗
PubMed1990

[Midazolam for rapid sequence induction].

We compared midazolam 0.2 mg.kg-1 and fentanyl 50 micrograms with thiamylal 4 mg.kg-1 for rapid sequence induction. We could use midazolam safely in patients with bronchial asthma or drug allergy. There was no difference in time from the beginning of induction to intubation between midazolam treated group and thiamylal treated group. Changes in systolic as well as diastolic blood pressure and heart rate during 2 hours from intubation were smaller in midazolam treated group than in thiamylal treated group. In midazolam treated group, no arrhythmias were observed at the time of intubation. We could reduce the amount of anesthetics in midazolam treated group during 2 hours from intubation. From the results mentioned above, we conclude that midazolam is a useful agent for rapid sequence induction.

Adult↗
PubMed1989

Correlation between reversing of multidrug resistance and inhibiting of [3H]azidopine photolabeling of P-glycoprotein by newly synthesized dihydropyridine analogues in a human cell line.

Ten synthetic dihydropyridine analogues were investigated for their ability to reverse drug resistance in a multidrug-resistant human carcinoma cell line, KB-Cl. Four dihydropyridine analogues completely reversed the resistance, three lowered the resistance, and three had little effect. The radioactive photoactive dihydropyridine calcium channel blocker, [3H]azidopine, photolabels P-glycoprotein in membrane vesicles from KB-Cl cells. This photolabeling was almost completely inhibited by excess dihydropyridine analogues that reversed or lowered drug resistance. In contrast, the labeling was not significantly inhibited by analogues that do not reverse resistance. Among other reversing agents, cepharanthine and reserpine inhibited the [3H]azidopine photolabeling, but thioridazine did not. N-Solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine slightly inhibited the labeling at 100 microM. An anticancer agent, vinblastine, also inhibited the labeling. The correlation between the reversing of the drug resistance and the inhibition of the [3H]azidopine photolabeling of P-glycoprotein by dihydropyridine analogues suggests a role for P-glycoprotein in multidrug resistance and also the reversing of the resistance by dihydropyridine analogues.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

Excitatory influence of the accessory olfactory bulb on tuberoinfundibular arcuate neurons of female mice and its modulation by oestrogen.

The role of the accessory olfactory bulb in conveying pheromonal information to tuberoinfundibular arcuate neurons was examined electrophysiologically in chloral hydrate-anaesthetized, oestrogen (0.5 micrograms in silastic capsules)-treated and untreated ovariectomized Balb/c female mice. Electrical stimulation of the accessory olfactory bulb orthodromically excited part of tuberoinfundibular neurons which were antidromically stimulated from the median eminence and histologically verified as being located within the arcuate nucleus. No inhibitions followed accessory bulb stimulation. The excitatory response to accessory bulb stimulation was reversibly blocked by the local anaesthetic lignocaine infused into the amygdala. The percentage of tuberoinfundibular arcuate neurons responding to accessory bulb stimulation was significantly higher in oestrogen-treated than in untreated animals. There was no difference between the two groups for the antidromic activation threshold, spontaneous firing rate, absolute refractory period or frequency of successful antidromic propagation into the soma of tuberoinfundibular arcuate neurons. In oestrogen-treated preparations, tuberoinfundibular arcuate neurons responsive and unresponsive to accessory bulb stimulation could be distinguished by the frequency of successful antidromic propagation into the soma. These studies demonstrate that olfactory relay neurons in the accessory olfactory bulb act to enhance the activity of a subpopulation of tuberoinfundibular arcuate neurons via the amygdala and that this neural transmission is modulated by oestrogen.

Action Potentials↗
PubMed1989

Influence of microinjection of glucagon into the amygdala on hepatic acetate metabolism in rabbits.

Glucagon was injected directly into the medial amygdala (AMYG) of rabbits, and changes in hepatic acetate metabolism were studied. The injection of 3 ng glucagon into the AMYG of intact rabbits increased the rates of 14C transfer from 14C-1-acetate into CO2, glucose, ketone bodies, cholesterol ester, free fatty acids and phospholipids but decreased those of 14C transfer into triglyceride. However, the glucagon injection into the AMYG of rabbits with lesions of stria terminals or into the parietal cortex of intact rabbits had no effects on the hepatic acetate metabolism. These observations support the hypothesis that the AMYG is a part of the glucagon-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1989

Influence of electrical stimulation of the limbic structure on adrenocortical steroidogenesis in hypophysectomized rats.

The effects of electrical stimulation of the medial amygdala (AMYG) and dorsal hippocampus (DHPC) on the rates of 14C transfer from 14C-1-acetate into adrenocortical steroids in adrenal slices of hypophysectomized rats were investigated. The 14C transfer rates into corticosterone were increased by stimulation of the AMYG and DHPC. The 14C transfer rates into cortisol were increased by the AMYG stimulation but were not altered by the DHPC stimulation. From these results, it might be suggested that these limbic structures were involved in the regulation of adrenocortical steroidogenesis without participation of the pituitary.

Adrenal Cortex Hormones↗
PubMed1989

Preparation of Mycoplasma hyopneumoniae antigen for the enzyme-linked immunosorbent assay.

Methods of preparation of Mycoplasma hyopneumoniae antigens for the enzyme-linked immunosorbent assay to detect specific antibody, and properties of the antigens, are described. The reactivity and specificity of antigen prepared by Sephacryl S-300 column chromatography after treatment of M. hyopneumoniae cells with Tween 20 (S-300 antigen) were superior to those of antigen prepared by Sephadex G-25 column chromatography after treatment with Tween 20, or to lipid antigen. There were no differences among strains MI-3, J and VPP11 of M. hyopneumoniae. The S-300 antigen did not show cross-reactivity against porcine hyperimmune sera produced by M. hyorhinis, M. hyosynoviae, M. hyopharyngis, M. flocculare and Acholeplasma granularum. Antibody was first detected in sera of pigs inoculated intranasally with M. hyopneumoniae at two to four weeks after inoculation and seven to eight weeks after pigs were contact-exposed to the same mycoplasma.

Animals↗
PubMed1989

[A molecular basis for multidrug resistance and reversal of the resistance].

Multidrug-resistance is frequently characterized by enhanced drug efflux resulting from a membrane glycoprotein of 170,000 daltons (P-glycoprotein). Analysis of cloned cDNAs for the human MDR 1 gene, whose product is the P-glycoprotein, indicates that P-glycoprotein is an energy-dependent drug-efflux system for cytotoxic hydrophobic anticancer drugs. We have demonstrated that a photoanalog of a reversing agent, SDB-ethylenediamine, specifically binds to P-glycoprotein. The binding site on P-glycoprotein seems to be identical with that of anticancer agents and other reversing agents. On the other hand, the radioactive photoactive dihydropyridine calcium channel blocker, [3H] azidopine, photolabels P-glycoprotein in membrane vesicles from multidrug-resistant cells. This photolabeling is almost completely inhibited by excess dihydropyridine analogs that reverse or lower drug-resistance. In contrast, the labeling is not significantly inhibited by analogs that do not reverse resistance. These results suggest that it may be possible to quickly screen for dihydropyridine analogs that reverse multidrug resistance by measuring the inhibition of [3H] azidopine labeling of P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

[Bone scintigraphy in evaluation of the effect of renal transplantation in patients with renal osteodystrophy].

Bone scintigraphy before and after renal transplantation was studied in 14 patients with renal osteodystrophy. The radionuclide distribution patterns visualized on the images before transplantation were classified into two groups; one group with markedly increased tracer uptake throughout the whole skeleton, especially in the skull, another group with prominent tracer uptake in the soft tissues. These abnormal tracer accumulations improved after renal transplantation. Bone scintigraphy before and after renal transplantation provides useful information concerning the follow-up of patients with renal osteodystrophy.

Adult↗
PubMed1989

An immunological study of tricalcium phosphate supplied by three different manufacturers.

Antigenicity of tricalcium phosphate (TCP) ceramics which were supplied by two Japanese manufacturers and a manufacturer of United States was studied by means of delayed skin reactions in guinea pigs. Skin reactions were elicited 13 days after being immunized by intradermal injection of the ceramics into the dorsal flanks of guinea pigs. After 24 and 48 hr, these reactions were assessed by measuring the diameter of the erythema, the degree of hemorrhaging and its induration. Antigenicity was not detected in the TCP obtained from the Asahi Optical Co., Ltd. and the Kyocera Corporation by means of skin reactions. In contrast, TCP from Miter, Inc. (Synthograft) raised a delayed type hypersensitivity (DTH) 24 hr after antigen elicitation. The reaction appeared to be based on tuberculin type and Jones-Mote type of reactions. Arthus reactions were not observed in either the normal groups or groups immunized with TCP.

Animals↗
PubMed1989

[Bone scintigraphy in evaluation of the effect of renal transplantation in the patients with renal osteodystrophy].

Bone scintigraphy before and after renal transplantation was studied in 10 patients with renal osteodystrophy. The hemodialyses, which resulted in renal osteodystrophy, were maintained for years in all cases before renal transplantation. The radionuclide distribution patterns visualized on the images before transplantation were classified into two groups, that is, one group with markedly increased tracer uptake throughout the whole skeleton, especially in the skull, another group with prominent tracer uptake in the soft tissues. These abnormal increased tracer accumulation improved after renal transplantation. Bone scintigraphy before and after renal transplantation brings about a useful information concerning the follow-up of the patients with renal osteodystrophy.

Adult↗
PubMed1988

Involvement of the septum in the regulation of paraventricular vasopressin neurons by the subfornical organ in the rat.

Extracellular recordings were obtained from 58 phasically active neurosecretory neurons in the hypothalamic paraventricular nucleus (PVN) of urethane-anesthetized male rats. Of these PVN neurons, 39 exhibited an increase and 11 displayed a reduction in ongoing activity following electrical stimulation of the subfornical organ (SFO), while the remaining neurons were unresponsive. Microinjection of the local anesthetic lidocaine into the medial septum reversibly abolished the SFO stimulus-evoked reduction in 7 out of 9 PVN neurons tested, whereas similar injection was without effect on the stimulus-evoked increase in 18 out of 20 PVN neurons tested. These results suggest that the SFO efferents through the medial septum to the PVN exert a predominantly inhibitory influence on the excitability of putative vasopressin (VP)-secreting neurons in the PVN.

Action Potentials↗
PubMed1988

The median preoptic nucleus participates in the control of paraventricular vasopressin neurons by the subfornical organ in the rat.

Extracellular single-unit activity was recorded from phasically firing neurohypophyseal neurons (n = 41) in the hypothalamic paraventricular nucleus (PVN) of urethane-anesthetized male rats. Electrical stimulation of the subfornical organ (SFO) produced orthodromic long-duration (n = 18) or short-duration (n = 10) excitation or inhibition (n = 8) of the activity of PVN neurons. The long-duration excitatory response of about half (n = 7) the neurons (n = 15) tested was reversibly abolished by microinjection of the local anesthetic lidocaine into the median preoptic nucleus (MnPO), whereas neither the short-duration excitatory (n = 7) nor inhibitory (n = 6) responses were affected. These results suggest that the SFO efferents through the MnPO to the PVN may transmit the neuromodulatory signals which evoke long-duration increases in the excitability of putative vasopressin (VP)-secreting neurons in the PVN.

Action Potentials↗