Biomedical subjects

A Hosoyamada

Publications and source records attributed to A Hosoyamada.

At least 19 recordsLinked to original sources

PubMed2001

Antinociceptive efficacy of antidepressants: assessment of five antidepressants and four monoamine receptors in rats.

PURPOSE: For assessment of the antinociceptive potency of antidepressants, we compared the antinociceptive effects of serotonin selective reuptake inhibitors (SSRIs) and classical tricyclic antidepressants (TCAs) in rats. We also attempted to elucidate the monoamine receptor subtypes predominantly involved in the antinociceptive effect of antidepressants. METHODS: Male Wistar rats received SSRIs (sertraline, fluvoxamine, and citalopram) or TCAs (imipramine and desipramine) intraperitoneally, and the reaction time until pain response in the hot plate test and licking time in the formalin test were measured 60 min later. We also observed the effects of prazosin (an alpha(1) antagonist), WB-4101 (a selective alpha(1A) antagonist), yohimbine (an alpha(2) antagonist), WAY-100635 (a selective 5-HT(1A) antagonist), and ketanserin (a 5-HT(2) antagonist), which were simultaneously administered with imipramine or desipramine, on the antidepressant-induced antinociceptive effect in the formalin test. RESULTS: In the hot plate test, desipramine, 20 mg.kg(-1), but not imipramine or sertraline, produced a significant increase in reaction time. In the formalin test, desipramine and imipramine produced significant reductions in the licking time at over 5 mg.kg(-1) and at over 10 mg.kg(-1), respectively. These reductions were nearly complete at 20 mg.kg(-1). On the other hand, both SSRIs induced significant reductions in the licking time only at 20 mg.kg(-1). Prazosin, WB-4101, and ketanserin significantly antagonized the antinociceptive effect of 10 mg.kg(-1) of imipramine. However, imipramine-induced antinociception was not affected by yohimbine and WAY-100635. Prazosin and ketanserin also significantly suppressed antinociception by 5 mg.kg(-1) of desipramine. CONCLUSION: These findings suggest that classical TCAs are likely to have a therapeutic advantage over SSRIs for pain control. In addition, it is likely that central alpha(1) adrenoceptors and 5-HT(2) receptors are predominantly involved in imipramine- and desipramine-induced antinociception.

Journal Article↗

PubMed1999

Effects of chronic administration of glucocorticoid on midazolam pharmacokinetics in humans.

Midazolam (MDZ) is metabolized by CYP3A. Glucocorticoids are potent inducers of CYP3A in humans. The possible interaction between intravenous MDZ and chronically administered glucocorticoids was investigated during surgery in patients. MDZ (0.2 mg/kg) was administered intravenously to 8 patients taking glucocorticoid chronically and 10 patients not taking glucocorticoid. In patients taking glucocorticoid, the AUC0-infinity and CL of MDZ was decreased to 63.9% (16.3 +/- 10.5 vs 25.5 +/- 20.7 microg x min/mL) and increased to 127.5% (16.7 +/- 10.7 vs 13.1 +/- 8.3 mL/min/kg) of that in the control group, respectively. The terminal t1/2 values of MDZ were similar in two groups. In patients taking glucocorticoid, the AUC0-infinity of 1'-hydroxymidazolam (1'-OH MDZ) was 66.7% of that in the control group (7.6 +/- 2.6 vs 11.4 +/- 9.7 microg x min/mL), and the terminal t1/2 of 1'-OH MDZ was significantly (p < 0.01) decreased (1.8 +/- 0.5 vs 3.0 +/- 0.8 hr). Accumulative urinary excretion of 1'-OH MDZ glucuronide was increased to 157.6%. These observations might be results from induction of CYP3A4 and/or UDP-glucuronosyltransferase by glucocorticoids.

Adult↗

PubMed1998

[Clinical study of AJ-007 (bupivacaine) in spinal anesthesia--investigation of clinical dosage of isobaric and hyperbaric formulations].

Spinal anesthesia with two types of 0.5% bupivacaine hydrochloride solution, isobaric AJ-007 I and hyperbalic AJ-007 H, was studied clinically in 106 surgical patients with collaboration of 7 university hospitals. The following results were obtained. 1) Successful analgesia with motor block on abdominal wall and legs could be induced by dosages of 2.0 ml, 3.0 ml and 4.0 ml of either of the two solutions. 2) With isobaric solutions, the duration of the block was prolonged dose dependently. Anesthetic levels tended to increase and onset times of the block tended to decrease, with increasing dosage. 3) Hyperbalic solutions tended to produce higher levels of the block more rapidly. However, the duration of the block seemed to be shorter than that achieved by isobaric solutions. 4) The incidence of hypotension and bradycardia was similar to that observed in ordinary clinical spinal anesthesia. In one young male, a high level (C 2) of anesthesia was achieved after administration of 4.0 ml of hyperbaric solution. This patient was managed uneventfully under general anesthesia during the surgery. These results indicate that these two solutions of 0.5% bupivacaine are useful for spinal anesthesia.

Adult↗

PubMed1995

[Influence of the hypotensive anesthesia using halothane or trinitroglycerin on coronary blood flow--comparison of normal group and normovolemic hemodilution group].

We divided adult mongrel dogs under halothane anesthesia (1 MAC: 0.86%) into the normal group (N-group: no-hemodilution, with Hct 38 +/- 7%) and the hemodilutional group (H-group: normovolemic hemodilution, with Hct 38 +/- 4%-->21 +/- 4%). For dilution of blood, Dextran 70 was used. In both groups, control values of respiratory and circulatory parameters and coronary blood flow (CBF) were measured. We repeated these measurements after animals had been anesthetized by two different methods:halothane hypotensive anesthesia and trinitroglycerine hypotensive anesthesia. Under hypotensive anesthesia with halothane, CI, LV dp/dt max, and LVSWI decreased significantly as compared to control values in both group. CBF also decreased significantly as compared to the control values in both groups. Under trinitroglycerine hypotensive anesthesia, CI, LV dp/dt max and LVSWI decreased significantly from the control values in both groups as observed under halothane hypotensive anesthesia. Differing from these findings, under trinitroglycerine hypotensive anesthesia no difference from the control group was observed in CBF in N-group, while in H-group CBF decreased significantly from the control value. It was indicated from our results that the increase in coronary blood flow induced by trinitroglycerine becomes obscure under hemodilutional state.

Animals↗

PubMed1995

[Influence of hypotensive anesthesia on the organ blood flow--comparison of trinitroglycerine and nicardipine].

Adult mongrel dogs under anesthesia with 50% N2O + 0.5% halothane were further subjected to hypotensive anesthesia. For hypotensive anesthesia, we used two different drugs: trinitroglycerine (TNG-group) and nicardipine (NIC-group). In each of these groups, we measured respiratory and circulatory parameters and organ blood flow. The parameters of organ blood flow measured were renal cortical blood flow (RCBF), renal medullarly blood flow (RMBF), liver blood flow (LBF) and muscle blood flow (MBF). At the same time, distribution of organ blood flow was also determined. In TNG-group, significant decreases were observed in CI, LV dp/dt max, MPAP and PCWP due to decrease in venous return. In NIC-group, CI and LV dp/dt max increased significantly. No significant changes were seen in PaO2 in both groups. During hypotensive anesthesia organ blood flow decreased in all sites in TNG-group. However, as to blood distribution rate in TNG-group, RCBF and RMBF increased significantly, while a decreasing tendency was seen in MBF. On the other hand, in NIC-group RCBF decreased significantly, while MBF increased significantly. In NIC-group, distribution rate of RCBF, RMBF and LBF decreased significantly, but MBF showed a tendency to increase. From these results, it was indicated that hypotensive anesthesia using NIC may be associated with increased bleeding from the operative field due to increase in MBF.

Animals↗

PubMed1994

[Evaluation of the tolerance to hemorrhagic shock--comparison between hemodilution and non-hemodilution].

We induced various degrees of bleedings in adult mongrel dogs to determine their tolerance to bleedings. The dogs were divided into two groups: the hemodilution group (Group A: Hct 11.1 +/- 1.9%) and the non-hemodilution group (Group B: Hct 36.8 +/- 6.6%). The Group A tended to show higher tolerance to bleedings than the Group B, although the difference was not significant. Throughout the period of increasing degrees of bleedings, MAP remained higher in Group B than in Group A, but CI was higher in Group A than Group B. DO2I was kept higher in Group B than in Group A. Both PaO2 and PaCO2 showed no difference between the two groups. The results of our study indicate that hemodilution group tends to be more tolerant to bleeding than non-hemodilution group. The reason is probably that under hemodilution the oxygen delivery is maintained through an increase in cardiac output in the presence of decreased arterial oxygen content. In addition, it is considered that the safety is obtained through various factors such as preferential blood distribution to important organs (in particular to the myocardium), more efficient extraction of oxygen from the blood, and the decreased work load resulting from a reduced blood viscosity.

Animals↗

PubMed1994

[Comparison of a reflectance sensor and a transmittance sensor for pulse oximetry].

We have investigated a new optical reflectance sensor for pulse oximetry in 70 patients under general anesthesia. The reflectance sensor was applied to the forehead, the dorsal manus, the inguinal region, and the anterior crus of the patients. We could obtain a reliable SpO2 value when the reflectance sensor was applied on both forehead and anterior crus. It was difficult to obtain a reliable SpO2 value with the reflectance sensor without using an additional attachment especially for children. We compared the SpO2 value using the reflectance sensor attached to the forehead, with the SpO2 value obtained by the transmittance sensor attached to a finger or an ear lobe, in 7 volunteers who held the breath as long as possible. When we attached the probes on both ear lobe and forehead, the response time was faster, but and the maximum changing value was much larger, compared with those on the finger. We could obtain a reliable and stable SpO2 value using the reflectance sensor, when it was placed on the appropriate site as the forehead or the anterior crus.

Adolescent↗

PubMed1994

[Effects of total spinal block on the circulatory system and myocardial oxygen demand and supply balance].

Total spinal block with 1.5% lidocaine was performed in adult mongrel dogs, and its effects on circulatory system and myocardial oxygen demand and supply balance were investigated. The study demonstrates that the circulatory system is depressed under induced total spinal block, as manifested by a marked decrease in HR, MAP, CI, and LV dp/dt max. A decrease in SvO2 suggests that total spinal block places the animals in lack of oxygen supply. On the other hand, coronary arterial blood flow was significantly reduced by total spinal block. With reduction in myocardial oxygen consumption, however, coronary venous oxygen saturation (ScvO2) and myocardial oxygen extraction rate remained unaffected, and myocardial lactate uptake was also affected little. The results suggest that sufficient coronary arterial blood flow is maintained during total spinal block to respond to the myocardial oxygen demand. There is a possibility that myocardial oxygen demand and supply are well balanced under total spinal block.

Anesthesia, Spinal↗

PubMed1993

[A comparison of pancuronium and vecuronium used during the induction of high-dose fentanyl anesthesia].

Effects on hemodynamics and blood catecholamine levels of pancuronium and vecuronium used during the induction of anesthesia, were studied in patients undergoing coronary artery bypass grafting. Anesthesia was induced out with fentanyl, 70 micrograms.kg-1, and diazepam, 0.2 mg.kg-1, and either pancuronium or vecuronium was administered in a dose of 0.2 mg.kg-1. Control measurements were made before the induction of anesthesia. Hemodynamic parameters and blood levels of norepinephrine (NEP) and epinephrine (EP) were measured three minutes (S1) and ten minutes (S2) after tracheal intubation. The study showed that HR, AP, CI, and coronary perfusing pressure were more stable in the group of patients receiving pancuronium (group P) than in the group receiving vecuronium (group V) during the induction of anesthesia. LVSWI and RVSWI showed a comparable decline in both groups. While NEP was unaffected in group P during the induction of anesthesia, it decreased significantly at S1 and S2, compared with control (S0), in group V. On the other hand, EP decreased significantly at S1 and S2 during the induction of anesthesia in both groups, but group V showed a greater change. The results of this study suggest that pancuronium is more advantageous than vecuronium as a muscle relaxant used during the induction of high-dose fentanyl anesthesia.

Anesthesia, Inhalation↗

PubMed1993

[Effects of nicardipine on hemodynamics and skin blood flow--comparison between N2O-sevoflurane and N2O-isoflurane anesthesia].

Dividing the surgical patients into GOS (N2O-oxygen-sevoflurane anesthesia) group and GOI (N2O-oxygen-isoflurane anesthesia) group, we studied the effects of nicardipine on hemodynamics and skin blood flow under each anesthetic method. Control measurements were taken when the hemodynamic parameters were stable during surgery and the incremental doses of nicardipine (0.5 mg) were administered up to a total of 2.0 mg. The changes in hemodynamic parameters and skin blood flow were measured at the nicardipine dosage of 0.5 mg (S1), 1.0 mg (S2), 1.5 mg (S3), and 2.0 mg (S4). Heart rate tended to increase in both groups. Blood pressure, on the other hand, decreased at S1 and S2, but showed little change at S3 and S4 in both groups. Skin blood flow tended to increase in the GOS group, but in the GOI group little change in skin blood flow was noted at S1-S3. Skin blood flow tended to decrease at S4 in the GOI group.

Anesthesia, Inhalation↗

PubMed1993

[Effects of the volume of the reservoir bag and the amount of fresh gas flow on FRC during CPAP].

We have examined effects of the volume of the reservoir bag and the amount of fresh gas flow (FGF) on FRC during CPAP with PEEP level of 8 or 11 cmH2O. We used reservoir bags of 4 different volumes (5, 10, 15, 20l). We set up the air way pressure graduation between inspiration and expiration (delta P) by adjusting FGF rate, then we measured delta FRC and other respiratory parameters in 8 volunteers (26.3 +/- 0.8 yo). With the same PEEP level, delta P decreased but FRC increased by increasing FGF rate. When we used a lager reservoir bag, FGF rates which are necessary to set up the minimum delta P decreased during CPAP. We could obtain a larger delta FRC by using a larger reservoir bag compare with a smaller one, at the same delta P using same CPAP level. We should consider not only delta P but also the volume of the reservoir bag to obtain a reasonable and comfortable CPAP.

Adult↗

PubMed1993

[Influence of posture changes on hemodynamics under fentanyl-diazepam anesthesia--effects of nitrous oxide].

Patients for myocardial revascularization were divided into 50% oxygen-50% nitrogen group (group A) and 50% oxygen-50% nitrous oxide group (group B) according to the kind of gas administered after the induction of anesthesia. Anesthetic induction was carried out with fentanyl and diazepam in both groups. With sufficient hemodynamic stabilization following the induction of anesthesia, the hemodynamic parameters were measured in supine position for baseline data (BASELINE). The operating table was kept at Trendelenburg position (TREND), i.e., head down position, to measure hemodynamic parameters. Next, the operating table was kept at Fowler position (FOW), i.e., head up position, and hemodynamic parameters were measured. Heart rate was little influenced by posture change in both groups. While mean arterial pressure, mean pulmonary arterial pressure, central venous pressure and pulmonary capillary wedge pressure increased significantly in TREND in both groups, and decreased significantly in FOW. Cardiac index increased significantly in TREND in group A, but no such change occurred in group B. In FOW, cardiac index showed no significant change in group A, but decreased significantly in group B. Systemic vascular resistance was little influenced by posture change in both groups. This study suggests that it is necessary to exert a great caution in administering nitrous oxide when posture change is needed under fentanyl-diazepam anesthesia.

Anesthesia↗

PubMed1993

[Anesthetic management of a patient with carcinoid syndrome].

Anesthetic management of a 75-year-old female with carcinoid syndrome is reported. She had a tumor on the ileum and multiple metastatic tumors in the both lobes of the liver. Levels of both plasma serotonin and urinary 5-hydroxyindole acetic acid (5-HIAA) were significantly elevated before the operation. Although she was treated with somatostatin-analogue percutaneously, the levels of these hormones did not decrease significantly. The partial resection of the small intestine was scheduled under general anesthesia. Before induction of general anesthesia, hydrocortisone and ulinastatin were administered intravenously to prevent the release of chemical mediators. Anesthesia was induced with ketamine, diazepam, and vecuronium, and maintained with nitrous oxide, oxygen and enflurane. There was mild bronchospasm at the beginning of the surgery and the blood pressure was unstable during the operation, but anesthetic course was relatively uneventful. Although the patient recovered from anesthesia smoothly, she developed respiratory acidosis 45 minutes after extubation. She was intubated again and ventilated artificially with pressure support ventilation whose support level was 15 cmH2O for only three hours. We conclude that we should pay much attention not only during anesthesia but also after surgery, especially to respiratory system in patients with carcinoid syndrome.

Aged↗

PubMed1993

[The influence of normovolemic hemodilution on myocardial blood flow].

Normovolemic hemodilution was carried out in adult mongrel dogs by using SALIN-HES, and myocardial blood flow was measured by hydrogen clearance method. Moreover, distribution of the blood flow against cardiac output was calculated. The hematocrit levels before hemodilution was 40%. The hematocrit level by hemodilution (at 4 stages) were 26% at S1, 19% at S2, 9% at S3 and 5% at S4. Total of 4 localized myocardial blood flows in the outer and inner layer areas in both left and right cardiac ventricles were measured. All myocardial blood flows from S1 to S4 were significantly elevated by hemodilution and particularly the maximum level was observed at S3. The increase of the myocardial blood flow by hemodilution was larger in the left ventricle area than that in the right ventricle area. The distribution of the blood flow against cardiac output in the left ventricle area was elevated at S1 and S2, while no significant change was observed at S3 and S4. No significant change in the right ventricle area was observed from S1 to S4. The higher the degree of hemodilution, the higher was the decrease of blood flow ratio of the inner layer area/outer layer area in the left ventricle, but no change was observed in the right ventricle area.

Animals↗

PubMed1993

[Effect of hemodilutional autotransfusion on coagulative-fibrinolytic dynamics and metabolic response].

We studied the effect of hemodilutional autotransfusion on coagulative-fibrinolytic dynamics and metabolic response. Hemodilutional solutions used were Dextran-40 (group A) and Salin-HES (group B). The activated partial thromboplastin time (APTT) immediately after hemodilution was prolonged in both groups. Prothrombin time (PT) and hepaplastin decreased significantly, and a remarkable variation was observed particularly in group A. The results suggest that effect on fibrinolytic dynamics is not exerted in either group because antithrombin-III (AT-III) and fibrinogen decreased significantly, while fibrinogen degradation products (FDP) are within normal ranges, and plasminogen as well as alpha 2-plasmin inhibitor (alpha 2-PI) decreased significantly. On the other hand, all other parameters such as lactic acid level, pyruvic acid level in blood, lactic acid pyruvic acid ratio, and blood glucose level were elevated during surgery, but no difference was observed regarding these parameters between the two groups.

Adult↗

PubMed1992

[Influence of normovolemic hemodilution on the respiratory and circulatory systems].

We studied respiratory and circulatory kinetics of normovolemic hemodilution in adult mongrel dogs. The dogs were divided into two groups; Dextran-40 (group A) and SALIN-HES (group B). No difference in PaO2 and PaCO2 was noted between the two groups. MPA and CI during normovolemic hemodilution were higher in group A than in group B. However, MPA, Qs/Qt and ETVI during normovolemic hemodilution were largely influenced in group A. L/P during normovolemic hemodilution was more influenced in group B than in group A. The compensatory effect with increase of the cardiac output during normovolemic hemodilution was noted until S3 (Hct = 10%), but it was not noted at S4 (Hct = 5%) and S5 (just before death). SvO2 is the most sensitive index indicating the risk of normovolemic hemodilution.

Animals↗

PubMed1992

[Changes in myocardial blood flow and systemic hemodynamics during hypotensive anesthesia induced by adenosine triphosphate with or without dipyridamole].

The changes in myocardial blood flow and systemic hemodynamics during hypotensive anesthesia with adenosine triphosphate (ATP) or ATP with dipyridamole (0.5 mg.kg-1) were studied in 20 mongrel dogs anesthetized with 0.7% halothane in 100% oxygen. In both groups, mean arterial blood pressure (MAP) was reduced to 60 mmHg by intravenous administration of ATP. During hypotensive anesthesia, coronary blood flow, myocardial blood flow and cardiac index increased significantly in both groups. Lactic acid and uric acid increased significantly during hypotensive anesthesia in the group 1. Heart rate, MAP, systemic vascular resistance and coronary vascular resistance decreased significantly during hypotensive anesthesia in both groups. Mean pulmonary arterial pressure, pulmonary arterial wedge pressure and central venous pressure showed no significant changes in both groups. Base excess in the group 1 increased markedly compared with the group 2. We conclude that pretreatment with dipyridamole can prevent metabolic acidosis that occurs during hypotensive anesthesia induced by ATP.

Adenosine Triphosphate↗

PubMed1992

[Influence of normovolemic hemodilution on organ blood flow].

The normovolemic hemodilution was carried out in adult mongrel dogs by using SALIN-HES, and organ blood flow was measured by hydrogen clearance method, and the distribution rate of cardiac output to the organ was calculated. The organ blood flow was measured in the cerebral cortex (CCBF), liver (LBF) and renal cortex (RCBF). The hematocrit level before hemodilution was 42%. The subsequent hematocrit levels (at 4 stages) were 26% at S1, 18% at S2, 10% at S3 and 5% at S4. The results suggest that higher the degree of hemodilution, CCBF increases more, and that CCBF increased significantly from S2 to S4. However, no significant variation was observed in the distribution rates of the blood flow. Moreover, no significant variation by hemodilution was also observed in both LBF and RCBF. However, a significant decrease of the distribution rate of the blood flow was observed in LBF from S1 to S2 and RCBF from S2 to S4, and the higher the degree of the hemodilution is, the rate of blood flow decreased the more remarkably.

Animals↗