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Biomedical subjects

H Obara

Publications and source records attributed to H Obara.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

The effects of various peptides on the isolated pulmonary artery.

Helical strips of pulmonary arteries from rabbits were tested for their responses to the following peptides: neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), cholecystokinin-octapeptide (CCK), somatostatin (SS), bombesin, neurotensin and gastrin. SP, in the absence of active base-tension, and NPY both induced concentration-dependent contractions, while VIP and SP, in the presence of active base-tone, and CCK induced relaxation. The pD2 (-log ED50) was in the order of NPY greater than SP and SP greater than CCK greater than VIP. SS, bombesin, NT and gastrin had no effect. These findings suggest peptidergic involvement in the vessels.

Animals↗
PubMedDate not supplied

Effects of prostaglandin E1 on the cardiovascular response to tracheal intubation.

STUDY OBJECTIVE: To evaluate the efficacy of prostaglandin E1 in attenuating the hypertensive response to laryngoscopy and intubation. DESIGN: Controlled, comparative, and randomized study. SETTING: Induction of anesthesia for elective surgery at a university hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery divided into three groups. Each group consisted of ten patients. INTERVENTIONS: Anesthesia was induced with thiopental sodium 5 mg/kg intravenously, and tracheal intubation was facilitated with vecuronium 0.2 mg/kg. Either 0.3 micrograms/kg of prostaglandin E1, 0.6 micrograms/kg of prostaglandin E1, or saline (control) was injected 15 seconds before starting direct laryngoscopy (within 30 seconds), which was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were significantly less in prostaglandin E1-treated patients than in the control group (p less than 0.05). CONCLUSIONS: A single rapid intravenous administration of prostaglandin E1 is a practical pharmacologic and safe method to attenuate the hypertensive response to tracheal intubation. The use of 0.6 micrograms/kg of prostaglandin E1 as a supplement during induction is recommended for reducing the pressor response to intubation on the basis of rate-pressure product and mean arterial pressure following intubation as an index.

Alprostadil↗
PubMedDate not supplied

Effects of nilvadipine on the cardiovascular responses to tracheal intubation.

STUDY OBJECTIVE: To evaluate the efficacy of nilvadipine given orally in attenuating the hypertensive response to laryngoscopy and intubation. DESIGN: Controlled, randomized, double-blind study. SETTING: Induction of anesthesia for elective surgery at a university hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery were divided into three groups of ten patients each. INTERVENTIONS: Either 2 mg of nilvadipine, 4 mg of nilvadipine, or a placebo (control) was administered orally 90 minutes before induction of anesthesia. Anesthesia was induced with thiopental sodium 5 mg/kg intravenously, and tracheal intubation was facilitated with vecuronium 0.2 mg/kg. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide (N2O) in oxygen. Laryngoscopy lasting 30 seconds was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving the placebo showed a significant increase in mean arterial pressure (MAP) and heart rate associated with tracheal intubation. The increase in MAP following tracheal intubation was significantly lower in nilvadipine-treated patients than in the control group (p less than 0.05). However, neither dose of nilvadipine attenuated the tachycardic response to intubation. CONCLUSIONS: Oral administration of nilvadipine before induction of anesthesia is a simple and practical method for attenuating pressor response to laryngoscopy and tracheal intubation after standard elective induction under additional 1% enflurane-N2O anesthesia.

Administration, Oral↗
PubMedDate not supplied

Partial attenuation of the cardiovascular responses to tracheal intubation with oral nisoldipine.

STUDY OBJECTIVE: To evaluate the efficacy and safety of nisoldipine given orally in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Induction of anesthesia for elective surgery at a university hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery were assigned to one of three groups; placebo, nisoldipine 5 mg, or nisoldipine 10 mg. Each group consisted of ten patients. INTERVENTIONS: Either 5 mg of nisoldipine, 10 mg of nisoldipine, or a placebo was administered orally 2 hours before induction of anesthesia. Anesthesia was induced with thiopental sodium 5 mg/kg intravenously, and tracheal intubation was facilitated with vecuronium 0.2 mg/kg. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 seconds was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving the placebo showed a significant increase in mean arterial pressure associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in patients receiving nisoldipine 10 mg compared with patients receiving the placebo (p less than 0.05). CONCLUSIONS: Oral administration of nisoldipine before induction of anesthesia is a simple, practical, and safe method for attenuating pressor response to laryngoscopy and tracheal intubation.

Administration, Oral↗
PubMedDate not supplied

Attenuation of hypertensive response to tracheal intubation with nitroglycerin.

STUDY OBJECTIVE: To evaluate the efficacy and safety of intravenous (IV) nitroglycerin in attenuating the hypertensive response to laryngoscopy and intubation as a new application of the drug. DESIGN: Controlled, randomized, double-blind study. SETTING: University hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery were divided into three groups of ten patients each. INTERVENTIONS: Anesthesia was induced with thiopental sodium 5 mg/kg i.v., and tracheal intubation was facilitated with vecuronium 0.2 mg/kg i.v. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Either 1.5 micrograms/kg of nitroglycerin, 2.5 micrograms/kg of nitroglycerin, or saline (control) was administered IV simultaneously with the start of laryngoscopy (lasting 30 seconds), which was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in nitroglycerin-treated patients compared with those in the control group (p < 0.05). CONCLUSION: A single, rapid IV dose of nitroglycerin is a simple, practical, effective, and safe method to attenuate the hypertensive response to laryngoscopy and tracheal intubation.

Adult↗
PubMedDate not supplied

The effects of sarpogrelate on superoxide production by human neutrophils.

BACKGROUND AND OBJECTIVES: Superoxide anion (O2-) released from neutrophils plays an important role in antibacterial host defense system and tissue auto-injury. Sarpogrelate, a serotonin-receptor antagonist, has been successfully used for management of chronic pain caused by arterial occlusive or ischemic vascular diseases, or by microcirculation disturbances. Suppression of O2- generation may be detrimental to infection or contribute to the therapeutic approach to these diseases, the pathogenesis of which probably includes neutrophil activation. No data regarding the effects of sarpogrelate on neutrophil functions are available despite the possible clinical concern. The purpose of this study was to determine whether sarpogrelate reduces O2- production by human neutrophils using an in vitro system. In addition, we examined changes in concentrations of the intracellular calcium ion ([Ca2+]i), which is responsible for one of the mechanisms of the neutrophils' O2- production. METHODS: The O2- production by human neutrophils or the xanthine-xanthine oxidase system and [Ca2+]i were measured in the absence and the presence (at clinically relevant concentrations: 0.1x, 10x, and 100x these concentrations) of sarpogrelate. RESULTS: Sarpogrelate inhibited O2- production of neutrophils in a dose-dependent manner. The drug at a clinically relevant concentration suppressed this neutrophil function. In contrast, sarpogrelate failed to inhibit O2-generation by the cell-free (xanthine-xanthine oxidase) system. Elevation of [Ca2+]i in neutrophils stimulated by a chemotactic factor was dose-dependently attenuated with sarpogrelate. CONCLUSIONS: These findings suggest that sarpogrelate (even at clinically relevant concentrations) is able to inhibit O2- production by neutrophils. However, the drug failed to quench an excessive amount of O2- (similar to the level produced by neutrophils). There is a possibility that the inhibitory effect of the drug on [Ca2+]i response in neutrophils may contribute to impairment of the neutrophils' O2- production. Further studies using in vivo systems are required to elucidate the inhibitory effects of sarpogrelate on O2- in clinical settings.

Calcium↗
PubMedDate not supplied

Effect of dopamine on plasma growth hormone and prolactin concentrations under anaesthesia.

Five patients with acromegaly and five patients with prolactinoma undergoing general anaesthesia were studied. Concentrations of plasma growth hormone in patients with acromegaly and concentrations of plasma prolactin in patients with prolactinoma were measured before anaesthesia, when 250 mg levodopa was administered orally, and after anaesthesia when dopamine was infused intravenously at a rate of 5 micrograms/kg.min. There was no difference in hormonal (growth hormone or prolactin) response to either treatment in the anaesthetized and the awake states. These findings indicate that the functioning of dopamine receptors in the anterior pituitary is not affected by anaesthesia.

Acromegaly↗
PubMedDate not supplied

Inhibitory effect of barbiturates and local anaesthetics on protein kinase C activation.

A calcium- and phospholipid-dependent protein kinase C subspecies purified from rat brain was inhibited by thiamylal, thiopentone, pentobarbitone, mepivacaine and bupivacaine. This was attributed to the inhibition of the activation process rather than to direct interaction with the active site of the enzyme. It is well established that unsaturated diacylglycerol markedly increases the affinity of protein kinase C for calcium ions. Kinetic analysis suggested that pentobarbitone brought about the inhibition by competing with the diacylglycerol diolein and that mepivacaine and bupivacaine competed with the phospholipid phosphatidylserine used in the assay. The possibility exists that the effects of local anaesthetics on the function of various tissues are due, in part, to an inhibitory action on protein kinase C.

Anesthetics, Local↗
PubMedDate not supplied

Effects of diazoxide on the cardiovascular response to tracheal intubation.

The efficacy of 2 or 3 mg/kg diazoxide given 2.5 min before laryngoscopy in attenuating the cardiovascular responses to laryngoscopy and intubation was studied in 30 patients undergoing elective surgery. Data were compared with those from 10 control patients receiving saline. Anaesthesia was induced using 5 mg/kg thiopentone given intravenously and tracheal intubation was facilitated with 0.2 mg/kg vecuronium bromide. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. The increases following tracheal intubation were significantly reduced (P less than 0.05) in diazoxide-treated patients compared with those in the control group, but there were no significant differences in heart rate following tracheal intubation among the three groups. Data suggest that diazoxide can be used as a supplement during induction of anaesthesia to attenuate the hypertensive response associated with laryngoscopy and tracheal intubation.

Adult↗
PubMedDate not supplied

Development of Bell's palsy despite treatment of post-traumatic headache by stellate ganglion block.

It is a controversial issue whether or not stellate ganglion block (SGB) is an effective treatment for facial palsy. A case report is presented in which a patient with traumatic cervical syndrome developed Bell's palsy after being treated by same-side SGB, suggesting that SGB was not able to prevent development of Bell's palsy. The need for further clinical investigations on efficacy of SGB against Bell's palsy seems to be justified.

Adult↗
PubMedDate not supplied

Prostaglandin E1 and tracheal intubation: relationship between the cardiovascular responses and plasma catecholamine concentrations.

A study was carried out on 30 normotensive patients (American Society of Anesthesiologists physical status 1) to investigate whether or not a suppressive effect of 0.3 or 0.6 microgram/kg prostaglandin E1 on the hypertensive response to tracheal intubation was due to inhibition of the increase in plasma catecholamine concentrations following the stressful stimulation. A total of 30 patients in three groups underwent elective surgery. Anaesthesia was induced with 5 mg/kg sodium thiopentone given intravenously and tracheal intubation was facilitated by 0.2 mg/kg vecuronium. Either saline (group A) or 0.3 (group B) or 0.6 micrograms/kg (group C) prostaglandin E1 was administered intravenously 15 s before direct laryngoscopy (lasting 30 s) which was attempted 2 min after administering thiopentone and vecuronium. All groups exhibited significant (P less than 0.05) increases in mean arterial pressure, heart rate, rate-pressure product and plasma noradrenaline concentrations following tracheal intubation, but the increases in mean arterial blood pressure and rate - pressure product were significantly (P less than 0.05) less in groups B and C than in group A. Prostaglandin E1, however, enhanced the increase in plasma noradrenaline concentrations following intubation. Data suggest that attenuation of the pressor response to intubation by prostaglandin E1 may not be due to inhibition of the noradrenaline release stimulated by intubation but to inhibition of noradrenaline-induced vasoconstriction.

Adult↗
PubMedDate not supplied

Use of prostaglandin E1 to treat peri-anaesthetic pulmonary hypertension associated with mitral valve disease.

Severe pulmonary hypertension (PH) can be a critical problem during and after cardiac surgery, since it increases right ventricular afterload resulting in decreased cardiac output. A case of pulmonary hypertension associated with mitral valve disease and resistant to glyceryl trinitrate therapy during surgery is reported. The case was treated successfully with prostaglandin E1 (PGE1), indicating that PGE1 can be used peri-operatively in a patient with refractory PH resistant to glyceryl trinitrate treatment.

Alprostadil↗
PubMedDate not supplied

Effect of superoxide dismutase on endothelium-dependent relaxation of aorta from endotoxin-treated rabbits.

To assess the protective effect of superoxide dismutase (SOD) on the endothelium of aorta in endotoxaemia, we investigated the production of endothelium-derived relaxing factor in aorta obtained from endotoxin-treated rabbits concomitantly receiving SOD or not. Thirty-two male Japanese white rabbits were randomly divided into four groups (n = 8 for each group): one group receiving saline as a placebo, a second receiving 5 mg/kg endotoxin intravenously, a third receiving 5 mg/kg endotoxin intravenously plus SOD, and a fourth receiving SOD alone. SOD was injected intravenously at a dose of 10,000 U/kg before the endotoxin and was infused continuously at a rate of 15,000 units/kg/h throughout the experiment. The tension of the aorta was recorded in vitro 6 h after the start of in vivo treatment with endotoxin or saline. In the aorta of rabbits receiving endotoxin alone, acetylcholine-induced relaxation was reduced by 50%. The SOD fully restored the reduction of acetylcholine-induced relaxation by endotoxin. Histological studies using photomicroscopy revealed endothelial damage in the endotoxin-treated aorta, which was attenuated in the SOD-treated group. These data suggest that intravenous SOD may be an effective treatment for unstable haemodynamics in endotoxaemia.

Acetylcholine↗
PubMedDate not supplied

Inhibitory effect of gabexate mesilate on human neutrophil function.

Neutrophils accumulated in the lung are thought to play a key role in the pathogenesis of adult respiratory distress syndrome and interstitial pneumonia following bone-marrow transplantation. The effects of gabexate mesilate on several aspects of human neutrophil function have been investigated. Gabexate mesilate significantly decreased both the generation of reactive oxygen species (O2-, H2O2, OH.) by neutrophils and neutrophil chemotaxis. In contrast, the drug did not affect the levels of reactive oxygen species generated by a cell-free reactive-oxygen-species generating system. Intracellular calcium concentrations in neutrophils stimulated by f-Met-Leu-Phe were decreased in the presence of gabexate mesilate. These data suggest that the reduction in reactive-oxygen-species production and neutrophil chemotaxis by gabexate mesilate may contribute to the effectiveness of the drug in adult respiratory distress syndrome and interstitial pneumonia after bone-marrow transplantation. The suppression of the increase in intracellular calcium concentration may at least be responsible for the inhibition of these neutrophil functions by gabexate mesilate.

Calcium↗
PubMedDate not supplied

Acceleration of phagocytosis in human neutrophils incubated with gabexate mesilate.

It has recently been shown that gabexate mesilate inhibited human neutrophil functions including chemotaxis and reactive oxygen species production. In the present study, the effects of gabexate mesilate on phagocytosis by human neutrophils in vitro were investigated. Gabexate mesilate significantly enhanced neutrophil phagocytosis in a dose-dependent manner. This characteristic of gabexate mesilate may facilitate protection against infecting micro-organisms, although the inhibition of reactive oxygen species production by neutrophils may be a disadvantage for host-defense against infection.

Analysis of Variance↗
PubMedDate not supplied

Technique for iliac artery reconstruction in abdominal aortic aneurysm repair.

The aim of this retrospective study was to evaluate the technique for iliac artery reconstruction in abdominal aortic aneurysm repair, when external and internal iliac arteries were required to reconstruct individually. Among 203 elective infrarenal abdominal aortic aneurysm repairs, 22 patients (10.8%) required individual reconstruction of bilateral or unilateral iliac arteries, including 56 external or internal iliac arteries. Mainly, three types of procedures were performed: (1) the external iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end manner, and the internal iliac artery was attached to the side of the external iliac artery, (2) the external iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end manner and the internal iliac artery was bypassed with the use of a straight prosthetic graft extending from the limb of the bifurcated graft, and (3) the internal iliac artery was anastomosed to the end of the bifurcated graft limb in an end-to-end fashion, and the external iliac artery was sewn to the side of the graft limb. In these three types of procedures, the third technique was the easiest and simplest anatomically.

Aged↗