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Biomedical subjects

H Tsuchida

Publications and source records attributed to H Tsuchida.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Stent graft treatment for two cases of DeBakey IIIb dissecting aortic aneurysm].

Two patients with DeBakey IIIb dissecting aortic aneurysms were treated with transluminally placed endovascular stent grafts. Surgery was required for both patients because the false lumens were not thrombosed for several months. Stent graft devices composed of several units of self-expandable Z stents covered with ultra-thin woven Dacron were inserted through 18 Fr sheathes via femoral arteries. The stent grafts were deployed successfully and blood flow into the false lumens was reduced immediately and finally thrombosed without blood leakage from the entries. The endoluminal stent graft treatment is minimally invasive operation in comparison with former surgical operations, and is useful for aortic aneurysms especially in high risk patients. However, improvement of the stent graft devices, including the delivery systems such as the dilator, sheath and pushing rod, which are incomplete, and developing better devices, is required to reduce delivery failure and to make the stent graft treatment more reliable.

Aged↗
PubMed1997

[Evaluation of postoperative hypoxemia after spinal anesthesia with a pulse oximeter].

We investigated postoperative hypoxemia after spinal anesthesia in 24 adult patients by monitoring SPO2 with a pulse oximeter for 5 hours in the ward. The patients received spinal anesthesia with 0.5% hyperbaric tetracaine and sedated with midazolam during operation. Twelve patients inhaled 3 l.min-1 oxygen via a mask for initial 3 hours, and the other breathed room air all the time. In two of the patients breathing room air, SPO2 decreased to less than 94%. In patients inhaling oxygen, SPO2 was maintained above 98% but decreased significantly after stopping oxygen inhalation (below 94% in five patients). The postoperative SPO2 value correlated significantly with BMI (body mass index) and preanesthetic SPO2, but not with the dose of midazolam or supplemental pentazocine, and postoperative conscious states. In conclusion, there are some incidences of postoperative hypoxemia after spinal anesthesia irrespectively of the dose of midazolam used intraoperatively. Inhalation of 3 l.min-1 oxygen via a mask is sufficient to prevent such postoperative hypoxemia.

Adolescent↗
PubMed1997

[Effect of nicotine-administration on tyrosine hydroxylase-containing neuron in the rat forebrain; immunohistochemical study with semiquantitative morphometric analysis].

Nicotine is toxic substance that is absorbed by cigarette smoking and easily causes dependence. It is clear that smoking is bad for health, however, the effects of nicotine itself on the central nervous system have not been elucidated. We studied the effects of nicotine-administration (5 mg/kg x 2/day, 7 days) on immunoreactivity for tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine synthesis, in the rat forebrain including the cerebral cortex, hippocampus, striatum and hypothalamus to investigate the influence on catecholaminergic neurons. In the nicotine-administration group, both the number and intensity of TH-immunoreactive fibers and terminals increased in the fronto-parietal cortex, anterior cingulate cortex and hippocampus in comparison with those of the control group, and a significant difference was demonstrated by computer assisted morphometric analysis. These findings suggest that nicotine-administration influences catecholaminergic neural systems in the forebrain, especially in the cerebral cortex and hippocampus and that these effects might be related to developing the dependence on smoking.

Animals↗
PubMed1997

[Role of tumor necrosis factor-alpha in insulin sensitivity and effect of low protein diet on the TNF-alpha response in patients with diabetic renal failure].

In patients with diabetic renal failure, attention must be paid to the prevention of atherosclerosis as well as the preservation of renal function. Insulin resistance is one of the important risk-factors of atherosclerosis and the involvement of tumor necrosis factor-alpha (TNF-alpha) has been shown in the pathogenesis of insulin resistance in some diseases. A low-protein diet (LPD) is recommended for patients with advanced renal disease, but a large proportion of the total caloric intake is supplied from carbohydrates and fat in LPD. Therefore, we designed a study to determine: (1) the effect of TNF-alpha on insulin sensitivity, and (2) the effect of LPD on the TNF-alpha response and the risk factors of atherosclerosis, such as insulin sensitivity and lipid metabolism, in patients with diabetic renal failure. Insulin sensitivity was measured by an euglycemic hyperinsulinemic clamp technique and serum TNF-alpha level and in vitro release of TNF-alpha from peripheral blood mononuclear cells (PBMCs) was measured in patients with diabetic renal failure. A significant negative correlation was observed between lipopolysaccharide-stimulated TNF-alpha release from PBMCs and insulin sensitivity (r = -0.58, p < 0.05). Secondly, risk factors of atherosclerosis were measured before and two weeks after the introduction of LPD in patients with diabetic renal failure. LPD did not have any significant effect on insulin sensitivity, the production of TNF-alpha by PBMCs, lipid metabolism and glucose metabolism. These results indicate that: (1) TNF-alpha derived from PBMCs might affect insulin sensitivity in patients with diabetic renal failure, and (2) LPD does not have any significant effect on the risk factors of atherosclerosis.

Diabetic Nephropathies↗
PubMed1997

[Two cases of severe metabolic acidosis after monitoring of evoked spinal cord potential].

Evoked spinal cord potential (ESCP) elicited by direct spinal cord stimulation has been applied to monitor the spinal cord function during spinal surgery. We report here two patients who showed excessive muscle contraction and developed severe metabolic acidosis as a result of the stimulation of spinal cord to measure ESCP. These changes were prevented by vecuronium administration prior to ESCP monitoring. These results suggest that excessive muscle contraction by direct spinal cord stimulation may lead to metabolic acidosis. In conclusion, the use of a non-depolarizing muscle relaxant is recommended to prevent the adverse effects of ESCP monitoring.

Acidosis↗
PubMed1997

Study of RNA structure by pyrene-labeled oligonucleotides.

Fluorescent-labeled oligonucleotides containing 2'-(1-pyrenylmethyl) uridine (Upy) that have G or C adjacent to 3'-site of Upy, I and II, respectively, showed a remarkable increase in the emission intensity when they hybridized with the complementary oligoribonucleotides (ORN). However such change was not observed when they hybridized with the complementary oligodeoxyribonucleotides(ODN). Tm values derived from the UV melting curves for I-ORN and II-ORN duplexes were 5 degrees C and 10 degrees C lower than the normal duplexes without Upy, respectively. The intensity of induced CD based on the pyrene groups for the I-ORN and II-ORN duplexes were a half of that for the corresponding I-ODN and II-ODN duplexes. These results suggest that pyrene groups were released from the stacking interaction upon duplex formation and that the remarkable change of emission intensity was then occurred. Based on these properties, it is suggested that Upy-probes that have G or C adjacent to 3'-site of Upy can be useful to search the single strand region of RNA.

Base Composition↗
PubMed1996

Effects of thoracic epidural anesthesia on changes in ischemic myocardial metabolism induced by intracoronary injection of endothelin in dogs.

OBJECTIVE: Thoracic epidural anesthesia (TEA) has been reported to alleviate ischemic damage to the myocardium. Endothelin, an endothelium-derived peptide and a potent coronary vasoconstrictor, may contribute to poor cardiac perfusion and ischemia. The objective was to examine regional myocardial metabolism during ischemia caused by intracoronary injection of endothelin with and without TEA. DESIGN: The three experimental groups and three treatments were randomized. SETTING: All studies were conducted in a university research laboratory. PARTICIPANTS: Thirty anesthetized dogs comprised the study groups. INTERVENTIONS: Study animals were divided into three groups of 10 animals each identified as normal saline (NS); TEA; and TEA + blood pressure controlled (TEA + BPC). The NS group had 0.5 mL/kg of normal saline injected into the T4-5 epidural space. The TEA group had 0.5 mL/kg of saline containing 1% lidocaine injected into the T4-5 space. The TEA + BPC group had blood pressure and heart rate maintained at pre-epidural injection values by partially occluding the descending aorta and by atrial pacing. Endothelin (15 pmol/kg) was bolus injected into the left anterior descending (LAD) artery of each heart. Systolic and diastolic blood pressure, heart rate, and LAD coronary blood flow (CBF) were monitored. Three minutes after injection of endothelin, myocardial tissue was sampled from the distribution of the LAD artery and from the control, left circumflex (LCx) artery. ATP, ADP, AMP, lactate, and pyruvate were measured by enzymatic methods. MEASUREMENTS AND MAIN RESULTS: It was found that in each group endothelin consistently decreased LAD CBF, but the decrease was less in the TEA + BPC group. In the tissue distribution of the LAD, the levels of ATP and energy charge potential were lower, and the level of lactate was higher in the NS group than in the TEA or the TEA + BPC groups (p < 0.01). CONCLUSIONS: These results confirm that (1) endothelin injected into the LAD artery decreases CBF and causes selective myocardial ischemia in a fashion similar to intravascular stenosis of the LAD rather than to mechanical occlusion and (2) TEA, with or without pressure support, lessens the degree of regional ischemia induced by injection of endothelin in the LAD.

Adenosine Triphosphate↗
PubMed1996

Preparation and specificity of antibodies to an anti-tumor beta-glucan, lentinan.

Antibodies against beta-glucan, lentinan from "Shiitake" (Lentinus edodes), were raised in the rabbit by subcutaneous immunization. Our antibodies did not recognize the other polysaccharides such as amylose, dextran, laminarin and galactan. It was proved that lentinan contents in mushroom could be measured by ELISA with the anti-lentinan antisera. Its contents were 3.5 mg/g fresh weight in Lentinus edodes. However, lentinan was not contained in Agaricus brazei, Agaricus bisporus and Ramaria bitrytis.

Animals↗
PubMed1996

The effects of sevoflurane, isoflurane, halothane, and enflurane on hemodynamic responses during an inhaled induction of anesthesia via a mask in humans.

A rapid increase in isoflurane or desflurane concentration induces tachycardia and hypertension and increases-plasma catecholamine concentration. Little information is available as to whether sevoflurane, halothane, and enflurane induce similar responses during anesthesia induction via mask. Fifty ASA physical status I patients, aged 20-40 yr, and scheduled for elective minor surgery, received one of four volatile anesthetics: sevoflurane, isoflurane, halothane, or enflurane. Anesthesia was induced with thiamylal, followed by inhalation of 0.9 minimum alveolar anesthetic concentration (MAC) of the anesthetic in 100% oxygen via mask. The inspired concentration of anesthetic was increased by 0.9 MAC every 5 min to a maximum of 2.7 MAC. Heart rate (HR) and systolic blood pressure (SBP) were measured before and every minute for 15 min during anesthetic inhalation. In the sevoflurane and isoflurane groups, venous blood samples were drawn to determine the concentrations of plasma epinephrine and norepinephrine 3 min after each increase in anesthetic concentration. Sustained increments in HR were observed after increases in inspired isoflurane concentration to 1.8 MAC and 2.7 MAC (peak changes of 15 +/- 3 and 17 +/- 3 bpm, respectively). Isoflurane also increased SBP transiently after the inspired concentration was increased to 2.7 MAC (peak change of 10 +/- 4 mm Hg). Enflurane increased HR after the inspired concentration was increased to 2.7 MAC (peak change of 9 +/- 2 bpm). In contrast, changes in sevoflurane and halothane concentrations did not induce hyperdynamic responses. Plasma norepinephrine concentration in the isoflurane group was significantly higher than that in the sevoflurane group during 2.7 MAC (P = 0.022). We propose that there is a direct relationship between airway irritation of the anesthetic and immediate cardiovascular change during an inhaled induction of anesthesia.

Adult↗
PubMed1996

Sigma receptor activation does not mediate fentanyl-induced attenuation of muscarinic coronary contraction.

Our overall goal was to investigate the mechanism by which fentanyl attenuates acetylcholine-induced contraction in porcine coronary artery. We tested the hypothesis that fentanyl attenuates muscarinic coronary contraction via sigma receptor activation. Left coronary artery vascular rings were isolated from porcine hearts and were suspended in organ chambers for isometric tension recording. In untreated coronary vascular rings, acetylcholine administration resulted in dose-dependent contraction. Fentanyl attenuated acetylcholine-induced contraction. The sigma ligands--(+)-pentazocine, (+)-cyclazocine, haloperidol, and 1,3-di-o-tolylguanidine--also inhibited acetylcholine-induced contraction. In contrast, the selective sigma ligand, (+)-3-(3-hydroxyphenyl)-N-(1-propyl) piperidine failed to have an inhibitory effect on acetylcholine-induced contraction. Moreover, metaphit (1-[1(3-isothiocyanatophenyl)cyclohexyl]piperidine), which causes irreversible acylation of sigma receptors, only inhibited acetylcholine-induced contraction when it was present in the organ chamber. We also assessed the effects of inhibiting various points in the signal transduction pathway distal to naloxone-sensitive opioid receptor activation on acetylcholine-induced contraction. Selective (glybenclamide) and nonselective (tetraethylammonium) K(+)-channel inhibition, guanosine triphosphate-binding protein inactivation (pertussis toxin), and Type 1 and Type 2 dopamine receptor inhibition all failed to alter the attenuating effect of fentanyl on acetylcholine-induced contraction. Thus, neither sigma or opioid receptor activation is a prerequisite for fentanyl-induced inhibition of muscarinic coronary contraction.

Acetylcholine↗
PubMed1996

Effect of volatile anesthetics with and without verapamil on intracellular activity in vascular smooth muscle.

BACKGROUND: Although halothane and isoflurane inhibit receptor agonist-induced smooth muscle contraction by inhibiting Ca2+ influx via the L-type voltage-dependent Ca2+ channels, their effects on pharmacomechanical coupling remained to be clarified. The intracellular action of both anesthetics was studied during agonist-induced contractions using the Ca2+ channel blocker verapamil. METHODS: Isolated spiral strips of rat thoracic aorta with endothelium removed were suspended for isometric tension recordings in physiologic salt solution. Cytosolic concentration of Ca2+ ([Ca2+]i) was measured concomitantly using fura-2-Ca2+ fluorescence. Muscle contraction was evoked by the receptor agonists with 30 nm norepinephrine or 10 microM prostaglandin F2 alpha (PGF2 alpha), followed by exposure to halothane, at 0%, 1%, 2%, and 3% or isoflurane, at 2% and 4%. The effects of the anesthetics were compared with those of 0.1-1 microM verapamil (n = 8 for each condition). To clarify the intracellular action of the volatile anesthetics on agonist-induced contractions, this procedure was repeated for the anesthetics only in the presence of 1 microM verapamil (n = 8 for each condition). The effects of both anesthetics were also examined in nonreceptor-mediated contractions evoked with a 1-microM dose of the protein kinase C activator, 12-deoxyphorbol 13-isobutylate, which increases the Ca2+ sensitivity of the contractile elements (n = 8 for each). RESULTS: Halothane, isoflurane, and verapamil suppressed norepinephrine-and PGF2 alpha-induced increases in muscle tension and [Ca2+]i in a concentration-dependent manner. The Ca2+-tension regression lines suggested that the volatile anesthetics reduced Ca2+ sensitivity of the contractile elements during PGF2 alpha-induced contraction. Pretreatment of the muscle strip with verapamil revealed that halothane and isoflurane released Ca2+ during norepinephrine-induced contraction and that [Ca2+]i-tension relationship was modulated during PGF2 alpha-induced contractions. Halothane at 2% and 3% and isoflurane at 4% suppressed 12-deoxyphorbol 13-isobutylate-induced increases in muscle tension, whereas they enhanced increases in [Ca2+]i, indicating that both anesthetics suppressed Ca2+ sensitivity during 12-deoxyphorbol 13-isobutylate-induced contraction. CONCLUSIONS: Verapamil pretreatment unmasked the intracellular action of the anesthetics. Halothane and isoflurane influenced pharmacomechanical coupling during agonist-induced contraction.

Anesthetics, Inhalation↗
PubMed1996

Color monitoring after replantation.

The recognition of postmicrosurgical minute skin color changes is an important element in assessing vascular insufficiency that has traditionally relied on a skilled microsurgeon's subjective clinical impression. This study investigates the use of a color monitor for the objective quantitative evaluation of such skin color changes. Twenty-two replanted digits were monitored postmicrosurgically with a color meter while deep skin temperature recordings, an established method of postmicrosurgical monitoring, were taken simultaneously. The results showed that the digits' clinical courses, namely, "uneventful," "necrosis," "congestion," and "acute arterial obstruction," showed characteristic patterns of postmicrosurgical circulation that were reflected in skin color change measurements. The reliability of the color measurements was confirmed by the deep skin temperature recordings. This study suggests that skin color after microsurgery can be evaluated quantitatively with the proposed color monitoring system and that this system is useful for the diagnosis of postmicrosurgical vascular insufficiency.

Adult↗
PubMed1996

Prevalence of inhabitants with anti-hepatitis C virus antibody in an area following an acute hepatitis C epidemic: age-and area-related features.

The northern district of R Town, Yamagata Prefecture, Japan, experienced an epidemic of acute hepatitis C during the 6 years following 1967. A mass survey health examination for hepatitis C virus (HCV) infection was performed on the inhabitants of this district aged 6 or over (4,655 people). Of the 3,094 inhabitants (66.5%) examined, 602 (19.5%) were anti-HCV antibody (anti-HCV) positive. Of the 602 anti-HCV positive subjects, 444 (73.7%) showed an anti-HCV cutoff index of over 4.0 (high titer), 54 (9.0%) showed 3.0 approximately 4.0 (middle titer), and 104 (17.3%) showed an index of under 3 (low titer). One hundred and sixty subjects, randomly selected, were examined for HCV RNA by nested polymerase chain reaction, and positive reactions were detected in 125 subjects (78.1%). The anti-HCV positive rate differed greatly between subjects younger than 40 years (18/1,289; 1.4%) and those 40 or over (584/1,805; 32.4%). Those who had lived in this district since before the acute hepatitis C epidemic had a high rate of positive anti-HCV. Among the 47 hamlets in this farming district, the hamlet with the highest rate (71.4%) was surrounded by other hamlets where the rates decreased as the distance from the high rate hamlet increased. The study suggested a marked regional accumulation of HCV infection in this district and an age-related difference in HCV infection rates. The cause of the accumulation was not identified, although the HCV infection in this district may have been spread during or before the acute hepatitis C epidemic and produced many HCV carriers.

Adolescent↗
PubMed1996

[Evaluation of postoperative hypoxemia with a pulse oximeter].

We investigated postoperative hypoxemia by monitoring of SPO2 with a pulse oximeter for the first 5 hours in the ward. Forty-eight adults were divided into the general anesthesia along (G) group and the combination of epidural and general anesthesia (E) group. The patients were randomly administered either 3 l. min(-1) oxygen with face mask for the initial 3 hours or room air. Postoperative Spo2 values in the patients who breathed room air in both groups were less than 94% in 33% of G group and 50% of E group. 3 l. min(-1) oxygen inhalation through the face mask was enough to avoid postoperative hypoxemia in both groups; the mean values of Spo2 were 99% in G group and 97.9% in E group. Spo2 rapidly and significantly decreased after stopping the oxygen inhalation to under 94% in 25% of G group and 58% of E group. Significant correlations were found between Spo2 levels and both age (R = 0.75) and preanesthetic Spo2 (R = 0.66) in G group. Spo2 was significantly lower in the patients whose anesthesia was stopped after 5 p.m. than in those who were weaned before 5 p.m. In conclusion, there is a high incidence of postoperative hypoxemia for several hours in the ward, which can be relieved by 3 l. min(-1) oxygen inhalation with face mask.

Adolescent↗