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Biomedical subjects

R Ishii

Publications and source records attributed to R Ishii.

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

A comparison of young and aged populations for the diphtheria and tetanus antitoxin titers in Japan.

The antitoxin levels for diphtheria and tetanus were measured with samples of a young group immunized with diphtheria-tetanus-acellular pertussis combined vaccine and those of an aged group, members of which had not received vaccination in their youth. In the young group members of which had already received basic immunization with diphtheria-tetanus-acellular pertussis combined vaccine, the levels of both antitoxins rose well after injection at 11 to 12 years old with diphtheria-tetanus combined toxoids and remained high until 20 years of age. In the aged group, more than 80% showed antitoxin levels above 0.01 u/ml for diphtheria, while all had levels below that for tetanus, except three persons with confirmed tetanus immunization history. Maintenance of the protective antitoxin levels in the population by vaccination is necessary to prevent outbreaks of infection among unvaccinated or only partially immunized persons.

Adolescent↗
PubMed1996

Sevoflurane anaesthesia for a patient with adult polyglucosan body disease.

PURPOSE: Adult polyglucosan body disease (APBD) is a rare neurological disorder of unknown cause characterized by four manifestations: upper motor neuron signs, peripheral neuropathy with motor and sensory loss, urinary incontinence, and dementia. The purpose of this report is to present a patient with APBD anaesthetized successfully with sevoflurane and nitrous oxide. CLINICAL FEATURE: A 51-yr-old man with APBD was scheduled for haemorrhoidectomy. Paraesthesia, dysaesthesia, distal muscular atrophy and fasciculation were recognized in the extremities. Dementia, bulbar paralysis and respiratory insufficiency were basent. Anaesthesia was induced with inhalation of sevoflurane and nitrous oxide, and the trachea was intubated without the use of muscle relaxants. Maintenance of anaesthesia was performed with sevoflurane (inspired concentration: 1.5-2.5%) and nitrous oxide (50%). Emergence from anaesthesia and the postoperative course were uneventful, and no exacerbation of neurological signs and symptoms was recognized. No postoperative analgesia was required. CONCLUSION: General anaesthesia and tracheal intubation with sevoflurane and nitrous oxide provided safe anaesthesia for a patient with APBD.

Anesthesia↗
PubMed1996

Dural caroticocavernous fistula with both ophthalmic arteries arising from middle meningeal arteries.

A 60-year-old woman presented with a dural caroticocavernous fistula (CCF) in whom both by ophthalmic arteries arose from the middle meningeal arteries instead of from the internal carotid arteries. Transarterial embolisation of the CCF was contraindicated because of the risk of blindness. Transvenous coil embolisation was therefore performed. Bilateral origin of the ophthalmic artery from the middle meningeal artery is extremely rare.

Brain Diseases↗
PubMed1996

Regional differences of endogenous ATP release in rabbit arteries.

The releases of endogenous ATP from ear, femoral, renal and pulmonary arteries of rabbit were compared. Adenyl purines, such as ATP, ADP, AMP and adenosine, and norepinephrine (NE) were quantified by HPLC-fluorescence detection and HPLC-electrochemical detection, respectively. In all four blood vessels, electrical stimulation (ES) at 16 Hz significantly increased overflow of adenyl purine and NE. ATP was the main largest among adenyl purine released; release of adenosine was very small. The rank order of amounts of total purine released by ES was ear artery > renal artery = femoral artery >> pulmonary artery. There was no significant difference among the amounts of NE release induced by ES from these four arteries. ES-induced purine release was notably reduced by denudation of endothelium and prazosin at 1 muM. Methoxamine, alpha 1-adrenoceptor agonist, also produced release of adenyl purines in the four arteries. The rank order of amount of total purine released was ear artery > renal artery = femoral artery >> pulmonary artery. These suggest that the sources of ATP released by sympathetic nerve stimulation, which seems to be alpha 1-adrenoceptors on endothelial cells, not distributed homogeneously in the vasculature.

Adenosine Diphosphate↗
PubMed1996

Free vascularized deep peroneal nerve grafts.

An ideal donor site for vascularized nerve grafts should have a constant anatomy, minimal functional loss after the nerve has been sacrificed, and a dependable blood supply parallel to the nerve over a relatively long distance. Creating a pedicle for a free vascularized deep peroneal nerve graft with the anterior tibial vessels seems to be a most suitable method for repairing long nerve gaps of over 20 cm and digital nerve defects with severe finger damage. Applications of this nerve graft to digital nerve losses with severely scarred beds created by avulsion injury, and two-stage reconstruction in some partial brachial plexus palsies (free vascularized nerve graft in the first stage and free vascularized muscle graft in the second stage) are well indicated. Advantages of this technique are: (1) A long nerve graft (up to 25 cm) can be obtained, and anomalies are rare (the nerve is absent in only 4 percent of cases). (2) The caliber of the vascular pedicle is large (approximately equal to 3 mm). (3) The nerve has a sufficient blood supply from the collateral blood vessels. (4) The graft can be easily obtained in the supine position. (5) A monitoring skin flap, based on the inferior lateral peroneal artery, can be attached to the nerve graft. (6) Sensory loss resulting from the sacrifice of the nerve covers a minimal area. (7) A donor scar on the anterior aspect of the lower leg is more acceptable than one on the posterior aspect because of less movement in walking. Disadvantages of this technique are: (1) Sacrifice of the large vessels in the lower leg may result in circulatory complications in the donor foot; to avoid this problem, preoperative angiography is recommended. (2) The donor scar is in an exposed area in female patients. (3) There may be temporary postoperative edema and disability in the donor leg.

Adolescent↗
PubMed1996

Atrioventricular conduction during adenosine-induced hypotension in dogs anaesthetized with sevoflurane.

We have studied the effects of adenosine-induced hypotension on A-H interval (atrioventricular (AV) nodal conduction time during sinus rhythm), St-H interval (intra-atrial plus AV nodal conduction time during atrial pacing), H-V interval (His-Purkinje conduction time) and H-S interval (total ventricular conduction time) by His-bundle electrocardiography in addition to surface electrocardiogram during both sinus rhythm and atrial pacing in nine dogs anaesthetized with 1 MAC of sevoflurane. Stepwise increases in infusion rates of adenosine to 0.1, 0.3, 0.5 and 1.0 mg kg-1 min-1 produced a dose-related decrease in mean arterial pressure from 91 (6) to 38 (2) mm Hg. Adenosine significantly increased the A-H interval at infusion rates of 0.5 mg kg-1 min-1 and above, and the St-H interval at 1.0 mg kg-1 min-1. The H-V and H-S intervals remained unchanged. Heart rate decreased significantly only at 1.0 mg kg-1 min-1 with a significant increase in the PR interval. Adenosine-induced hypotension did not have deleterious effects on AV conduction times and the surface electrocardiogram in dogs anaesthetized with 1 MAC of sevoflurane. This may indicate that the effects of adenosine on AV conduction were small and therefore are unlikely to be a contraindication to the use of adenosine for inducing hypotension in patients with initially normal conduction during sevoflurane anaesthesia.

Adenosine↗
PubMed1996

Effect of 8-sulfophenyl theophylline on endogenous noradrenaline release from sympathetic nerves of the rabbit ear artery.

1. The release of endogenous noradrenaline (NA) and adenyl purine (ATP, ADP, AMP and adenosine) from the rabbit ear artery, evoked by electrical stimulation (ES; 16 Hz), was examined. 2. ES evoked a significant release of NA and purine; the ratio of the amount of total purine released to NA released was approximately 180 on a molar base. 3. ES-evoked purine release was significantly reduced by the denudation of the endothelium and abolished by the alpha 1-adrenoceptor antagonist, prazosin (1 mumol/L). 4. ES-evoked NA release was significantly reduced by a P1-purinoceptor antagonist, 8-sulfophenyl theophylline (8SPT). Purine release was slightly reduced by 8SPT. 5. These results suggest that endogenous NA released by ES results in the release of a large amount of purine, which may, in turn, increase the release of NA by acting on prejunctional purinoceptors on sympathetic nerve terminals.

Animals↗
PubMed1996

Preclinical assessment of a new transdermal delivery system for clonidine (M-5041T).

The effects of a new transdermal delivery system for clonidine (M-5041T) on hypotensive effect, urine volume, plasma renin activity (PRA) and antidiuretic hormone (ADH) in spontaneously hypertensive rats (SHRs) were compared to the effects of the continuous infusion of clonidine. Both M-5041T (1.5 and 4.5 mg/kg) and the continuous infusion of clonidine (250 micrograms/kg/24 h) elicited hypotensive effects persisting for 12 hours or more. These effects were based on consistent plasma concentrations of clonidine. These two treatments produced diuresis followed by antidiuresis, which was remarkably observed by continuous infusion of clonidine. Single subcutaneous injection of clonidine (50 micrograms/kg) produced diuresis accompanied by increases in electrolytes corresponding to plasma levels of clonidine. M-5041T at 1.5 mg/kg did not affect PRA until 12 h, and produced an increase in PRA at 24 h. M-5041T at 4.5 mg/kg and the continuous infusion of clonidine resulted in a decrease in PRA at 2 and 1 h followed by an increase at 12 and 24 h, respectively. M-5041T at 1.5 mg/kg did not affect plasma levels of ADH. Plasma ADH did increase at 2 and 4 h accompanied by diuresis following M-5041T at 4.5 mg/kg or the continuous infusion of clonidine, respectively. Clonidine-induced diuresis was not at least due to the inhibition of ADH release. The decrease in urine volume observed by continuous infusion of clonidine may be due to decrease in renal blood flow based on stimulation of peripheral adorenoceptors of clonidine. These findings suggest that the increases in ADH and PRA are due to the compensatory effects related to both diuresis and the long-lasting hypotensive effect induced by high plasma concentrations of clonidine. Thus, it can be expected that M-5041T at 1.5 mg/kg showing the minimum effective plasma concentration of clonidine will not result in tolerance to the hypotensive effect of clonidine associated with the retention of sodium in SHRs.

Administration, Cutaneous↗
PubMed1996

Antihypertensive effects of a new transdermal delivery system for clonidine in genetic and experimental hypertensive rats.

The antihypertensive effects of a new transdermal delivery system for clonidine (CAS 4205-90-7, clonidine tape, M-5041T) were investigated in spontaneously hypertensive rats (SHR), 2-kidney, 1-clip renal hypertensive rats (RHR) and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. M-5041T (0.5-4.5 mg/kg) elicited a long-lasting hypotensive effect that was accompanied by bradycardia in a dose-dependent manner during 24-h patching on the backs of rats in all three hypertensive rat models. The hypotensive effect of M-5041T was more persistent than that of oral administration of clonidine (50 and 100 micrograms/kg) in both SHR and RHR. The most pronounced hypotensive effect of M-5041T was observed in DOCA-salt hypertensive rats. Plasma clonidine concentrations following transdermal application of M-5041T (1.5 mg/kg) were approximately 2-3 fold higher in DOCA-salt hypertensive rats compared with SHR. Electrical conductance of the skin surface, an index of the water content of the stratum corneum, was greater in DOCA-salt hypertensive rats than in SHR, suggesting that the delivery of clonidine may have been enhanced as a result of an increase in skin permeability due to the increase in water content of the stratum corneum in DOCA-salt hypertensive rats. Co-administration of M-5041T (0.5 mg/kg) with either trichloromethiazide (1 mg/kg, orally) or nifedipine (3 mg/kg, orally) at each sub-dose which affected both systolic blood pressure and heart rate produced significant hypotensive and bradycardic effects in SHR. Following repeated daily applications of M-5041T (1.5 mg/kg) for 7 consecutive days in SHR, significant hypotensive and bradycardic effects were produced at 6 h post-patching and then disappeared at 24 h post-patching in each trial. The plasma clonidine concentrations at 6 and 24 h post-patching were similar from the first to the seventh trial. No significant changes in blood pressure and heart rate were observed after termination of the regimen. These findings suggest that M-5041T could serve as an efficient and useful antihypertensive transdermal delivery system in humans without producing tolerance to the hypotensive effect and withdrawal syndrome after abrupt cessation of the treatment when used alone or with either a diuretic or a calcium channel blocker.

Administration, Cutaneous↗
PubMed1995

Relationship between histamine receptors in the brain and diazepam-induced hyperphagia in rats.

We investigated whether histaminergic neurons in the brain are involved in diazepam-induced hyperphagia in rats. Pretreatment with intracerebroventricular (ICV) injection of either histamine H1-receptor antagonist, pyrilamine (10 and 30 micrograms) or histamine H2-receptor antagonist, famotidine (3 and 10 micrograms) did not affect only diazepam (1 mg/kg, subcutaneous, SC)-induced hyperphagia in nondeprived rats, but also spontaneous feeding in food-deprived rats. In addition, pretreatment with ICV injection of histamine H3-receptor antagonist, thioperamide, and histamine H3-receptor agonist, (R) alpha methylhistamine, enhanced and inhibited diazepam-induced hyperphagia (1 mg/kg, SC) in nondeprived rats, respectively. However, thioperamide and (R) alpha methylhistamine did not affect spontaneous feeding in food-deprived rats. These findings suggest that histaminergic neurons are not directly involved in diazepam-induced hyperphagia in rats. Furthermore, enhancement or inhibition of diazepam-induced hyperphagia by histamine H3-receptor antagonist or agonist may occur via histamine H3-receptors localized in the other neurons in the rat brain.

Animals↗
PubMed1995

High potassium-evoked release of ATP from rabbit pulmonary artery via endogenous noradrenaline.

1. High potassium 30 mM and noradrenaline at 10 microM significantly evoked the release of ATP and produced remarkable vasoconstriction in the rabbit pulmonary artery. 2. Phentolamine and prazosin at 0.1 microM inhibited ATP release but not vasoconstriction by 30 mM potassium. 3. 30 mM potassium significantly evoked the release of noradrenaline. 4. There was a significant positive correlation between the amounts of release of total purines, sum of ATP, ADP, AMP and adenosine, and noradrenaline evoked by 30 mM potassium. 5. 30 mM potassium-evoked ATP release was significantly reduced by denudation of endothelium.

Adenosine Triphosphate↗
PubMed1995

Effects of graded infusion rates of propofol on cardiovascular haemodynamics, coronary circulation and myocardial metabolism in dogs.

We have studied the effects of a 30-min infusion of propofol 6, 9, 12, 15, 18 and 21 mg kg-1 h-1 on cardiovascular haemodynamics, coronary circulation and myocardial metabolism in 12 mongrel dogs. Mean plasma concentrations of propofol after infusion of 6 and 21 mg kg-1 h-1 increased from 2.9 (SEM 0.3) to 11.5 (0.1) micrograms ml-1. Propofol produced a progressive decrease in arterial pressure. Heart rate tended to decrease at 15, 18 and 21 mg kg-1 h-1 and cardiac index decreased significantly at infusion rates > or = 9 mg kg-1 h-1. Systemic vascular resistance tended to increase except at 21 mg kg-1 h-1 and left ventricular systolic and diastolic function were depressed. Both coronary sinus blood flow and myocardial oxygen consumption decreased in parallel with a decrease in left ventricular minute work index without producing lactate. Propofol produced progressive decreases in coronary blood flow and myocardial oxygen consumption but did not exert adverse effects on the coronary circulation.

Anesthetics, Intravenous↗
PubMed1995

Comparison of the effects of halothane, isoflurane, and sevoflurane on atrioventricular conduction times in pentobarbital-anesthetized dogs.

It is not known how sevoflurane affects the cardiac conduction system. We compared the effects of halothane, isoflurance, and sevoflurane on specialized atrioventricular (AV) conduction times in eight pentobarbital-anesthetized dogs. AV conduction times with three inhaled anesthetics at end-tidal concentrations of 1 and 2 minimum alveolar anesthetic concentration (MAC), were measured by His-bundle electrocardiography during both sinus rhythm and right atrial pacing at a slightly higher rate than sinus one. Heart rate and arterial pressure were simultaneously recorded. Halothane prolonged AV nodal conduction time during sinus rhythm (A-H interval) at 2 MAC compared with the control value, whereas isoflurane and sevoflurane did not alter the A-H interval, His-Purkinje conduction time (H-V interval), and ventricular conduction time (H-S interval) during sinus rhythm at 1 and 2 MAC. All three inhaled anesthetics did not change AV conduction times during right atrial pacing. No significant difference in AV conduction times was observed between isoflurane and sevoflurane. Heart rate during sinus rhythm remained unchanged despite a decrease in arterial pressure with three inhaled anesthetics. The property of sevoflurane and isoflurane which does not affect the cardiac conduction system may be important in the stability of the cardiac rhythm during anesthesia with these drugs.

Anesthesia, Intravenous↗
PubMed1995

Regional difference of endogenous ATP release in the pulmonary artery of rabbits.

1. The release of adenyl purines such as ATP, ADP, AMP and adenosine, from the pulmonary artery trunk (PAT), extrapulmonary artery (EPA) and intrapulmonary artery (IPA) were compared. 2. The amount of basal overflow of adenyl purines from the PAT was significantly smaller than those from EPA and IPA. There was no significant difference between the amount of the overflow from EPA and PAT. 3. Methoxamine, an alpha 1-adrenoceptor agonist, significantly increased the overflow of adenine nucleotides from the PAT, EPA and IPA, but did not increase those of adenosine. Methoxamine-induced release of adenyl purines from IPA was significantly larger than those from EPA and PAT. 4. These results suggest that an alpha 1-adrenoceptor-mediated mechanism for ATP-release is not homogeneously distributed in the pulmonary artery and a larger amount of ATP may be released in the peripheral part of the artery.

Adenosine↗
PubMed1995

Hypotensive effects of a new transdermal delivery system for clonidine (M-5041T) in spontaneously and renal hypertensive rats.

1. Antihypertensive effects of a new transdermal delivery system for clonidine (clonidine tape; M-50417) were investigated in spontaneously hypertensive rats (SHR), 2-kidney, 1-clip renal hypertensive rats (RHR) and deoxycorticosterone acetate/salt (DOCA/Salt) hypertensive rats. 2. M-5041T (0.5-4.5 mg/kg) elicited long-lasting hypotensive effects and bradycardia in a dose-dependent manner during 24 h patching in three hypertensive models compared with oral clonidine (100 mu g/kg). 3. The most hypotensive effect of M-5041T was observed in DOCA/salt hypertensive rats. 4. Co-administration of M-5041T with either trichloromethiazide (1 mg/kg, orally) or nifedipine (3 mg/kg, orally) at each dose without hypotensive effects per se induced significant hypotension in SHR. 5. Repeated administrations of M-5041T (1.5 mg/kg per day) for a consecutive 7 days produced significant hypotensive effects at postpatching 6 h, and recovered a postpatching 24 h in SHR. 6. Repetitive M-5041T administrations displayed no tolerance on the hypotensive effects and were devoid of any withdrawal syndrome. 7. These findings suggest that M-5041T may serve as an efficiently useful antihypertensive transdermal delivery system in humans.

Administration, Cutaneous↗
PubMed1995

Absence of tolerance to hypotensive effects of clonidine in spontaneously hypertensive rats.

Development of tolerance to the hypotensive effects of clonidine was investigated in spontaneously hypertensive rats (SHR). Clonidine (125 micrograms/kg/day) was administered subcutaneously for 5 weeks using an osmotic infusion pump. During the whole infusion period, significant hypotensive and bradycardiac effects were observed. Plasma clonidine concentrations were maintained relatively constant at about 2 ng/ml during the infusion period. On termination of treatment with clonidine, both the blood pressure and heart rate rapidly recovered to the control levels. These findings suggest that clonidine does not cause tolerance to its hypotensive effects in SHR with the present administration regimen.

Animals↗
PubMed1995

Retrieval of a migrated detachable coil--case report.

A 74-year-old female presented with intraventricular and subarachnoid hemorrhage due to probable rupture of a basilar artery (BA) aneurysm or a superior cerebellar artery (SCA) aneurysm. She was treated by endovascular therapy using detachable coils through the BA. The BA aneurysm was completely occluded, but part of a coil migrated into the BA from the SCA aneurysm during the procedure. The migrated coil was retrieved using a snare type endovascular retrieving device. The snare loop required concentric closure around the coil by simultaneous pulling of the corewire and a slight forward movement of the tip of the snare catheter. The SCA aneurysm was successfully occluded 1 week later using a shorter coil.

Aged↗