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Biomedical subjects

R Shimizu

Publications and source records attributed to R Shimizu.

At least 163 records · Page 9Linked to original sources
PubMed1994

Erythropoietin induces tyrosine phosphorylation and activation of phospholipase C-gamma 1 in a human erythropoietin-dependent cell line.

Erythropoietin (Epo) is the major regulator of the proliferation and differentiation of erythroid precursors through interaction with its receptor (Epo-R). Although Epo-R lacks a tyrosine kinase consensus sequence within its intracellular domain, the addition of its ligand to Epo-responsive cells, UT-7/Epo, induces the rapid and transient tyrosine phosphorylation of 145-, 130-, 80-, and 40-kDa cellular proteins. Tyrosine phosphorylation of these proteins occurred dose- and time-dependently. We showed that the tyrosine phosphorylated 145- kDa protein is identical to phospholipase C-gamma 1 (PLC-gamma 1). Tyrosine phosphorylation of this protein is detectable within 30 s and almost reaches the maximum at 1 min. This can last up to 10 min and declines thereafter. Additionally, in Epo-stimulated cells, PLC-gamma 1 become physically associated with 80- and 40-kDa proteins which have been tyrosine-phosphorylated in response to Epo. The activity of PLC-gamma 1 was also investigated using inositol 1,4,5-trisphosphate (Ins-P3) as an indicator. We found that stimulation of UT-7/Epo cells with Epo induces a significant accumulation of Ins-P3. This effect is dose-dependent and occurs very rapidly. The production of Ins-P3 can explain the Epo-induced mobilization of calcium from intracellular stores in these cells. These results demonstrate that Epo induces tyrosine phosphorylation and activation of PLC-gamma 1 to produce Ins-P3 and then it mobilizes calcium from intracellular stores. This signal transduction pathway may play a role in regulating the proliferation of erythroid cells.

Calcium↗
PubMed1994

Intraarterial combined immunochemotherapy for unresectable hepatocellular carcinoma: preliminary results.

An important objective for patients with unresectable hepatocellular carcinoma (HCC) is the development of effective chemotherapy. We administered a combination of biological response modifiers and anticancer agents to 24 patients with unresectable HCC. Each case had an implanted infuser port which was connected to a catheter placed in the hepatic artery for the intraarterial (i.a.) administration of chemotherapy. The following agents were administered to each patient: recombinant interleukin-2 (800,000 JRU/day infused i.a. continuously for 6 days/week); OK-432 (5 KE injected i.a. twice in 4 weeks and i.m. three times per week); Adriamycin (10 mg injected i.a. twice in 4 weeks); cyclophosphamide (300 mg injected i.a. twice in 4 weeks), and famotidine (40 mg/day administered orally). Objective response was assessed according to tumor size measured by computed tomography and angiography before and after treatment. We observed a complete response (CR) in 4, partial response (PR) in 3, minor response (MR) in 7, no change (NC) in 7, and progressive disease (PD) in 3. The response rate (CR+PR+MR) was 58.3%. The overall 2-year survival rate was 52%. The 2-year survival rate of the responders (CR+PR+MR) was 80%, while that of the non-responders (NC+PD) was 0%. There was a significant difference between the responders and non-responders in respect to survival rate (P < 0.05). The percentages of CD25+ cells, CD56+ cells, and Leu7-CD16+ cells and NK activity in the peripheral blood showed a significant increase following the regimen. Serum levels of tumor necrosis factor alpha TNF alpha rose after the initiation of OK-432. TNF alpha levels were higher in the responders than in the non-responders. Adverse effects included high fever (all patients) and severe transient hypotension (15 patients) that was controlled by conservative therapy. Combined immunochemotherapy administered intraarterially may be a new strategy for treating unresectable HCC.

Aged↗
PubMed1994

Methylmethacrylate bone cement does not release histamine in patients undergoing prosthetic replacement of the femoral head.

This study was designed to see if methylmethacrylate monomer bone cement released histamine in 13 patients undergoing total hip replacement surgery with a cemented prosthesis, compared with seven control patients receiving a cementless porous-coated prosthesis. Blood samples for plasma concentrations of histamine were obtained before the start of anaesthesia, immediately before insertion of methylmethacrylate bone cement into the shaft of the femur in the cemented fixation group or before insertion of the femoral component of the prosthesis in the cementless fixation group, and 15, 30 and 60 min after the start of implantation of the prosthesis. In both groups, changes in plasma histamine did not differ significantly from baseline before implantation of cement. There were no significant differences between groups. We conclude that methylmethacrylate bone cement does not release histamine during total hip replacement surgery.

Aged↗
PubMed1994

Sevoflurane and isoflurane protect against bronchospasm in dogs.

BACKGROUND: Halothane and isoflurane have been shown to be effective in reversing bronchoconstriction; however, the effects of sevoflurane have not been well defined. We studied whether sevoflurane, compared with isoflurane, attenuates bronchospasm in dogs. METHODS: Twenty-four dogs sensitized to Ascaris suum were assigned to three groups: control (n = 8), sevoflurane (n = 8), or isoflurane (n = 8). In all dogs, anesthesia was induced with pentobarbital. In the sevoflurane and isoflurane groups, the volatile anesthetics were administered at an end-tidal anesthetic concentration of 1 MAC throughout the study. After measurement of pulmonary resistance (RL) and dynamic pulmonary compliance (Cdyn) at baseline, A. suum antigen was administered intravenously into the systemic circulation to induce anaphylaxis, and RL and Cdyn were recorded continuously for 120 min after antigen challenge. RESULTS: Effects on RL and Cdyn were maximal 5 min after the start of systemic administration of antigen in all groups. Both 1 MAC sevoflurane and 1 MAC isoflurane significantly attenuated the increase in RL provoked by antigen challenge, but the attenuation from 10 to 15 min after challenge in the sevoflurane group was not significantly different from that in the control group. There was no significant difference in RL between sevoflurane and isoflurane. For both sevoflurane and isoflurane, attenuation of the decrease in Cdyn was not statistically significant. There was no significant difference in Cdyn between sevoflurane and isoflurane. CONCLUSIONS: Sevoflurane is as effective as isoflurane in attenuating bronchoconstriction associated with anaphylaxis in dogs. Sevoflurane may be a useful alternative to halothane, enflurane, or isoflurane in the treatment of bronchospasm in asthma or anaphylaxis.

Anesthetics↗
PubMed1994

Production of nitric oxide in anaphylaxis in rabbits.

To verify production of nitric oxide (NO) in anaphylaxis, we measured NO in peripheral tissue in anaphylactic rabbits using an NO-sensitive electrode. Rabbits were sensitized to horse serum, which was later administered over 10 s into the systemic circulation to induce anaphylaxis. Blood pressure (BP), central venous pressure (CVP), heart rate, and NO were recorded continuously for 80 min after antigen challenge. The NO-sensitive electrode was placed between the superficial abdominal fascia and the rectus abdominis fascia. The NO concentration increased to 3000-4800 pA (about 3-4.8 microM NO) within 4 min after initiation of anaphylaxis, at which time BP was decreased and CVP increased; however, NO production was continuously observed 30-60 min after antigen challenge, during which time changes in BP and CVP were not correlated with changes in NO concentration. In conclusion, NO production can be detected using an NO-selective electrode in anaphylactic rabbits.

Anaphylaxis↗
PubMed1994

Principal component analysis, using the measurements during running and swimming test, in thoroughbred horses.

To investigate whether the running exercise fitness of individual horses could be assessed by a standardized swimming exercise test, the results of multivariate analysis of the exercise parameters measured during incremental running and swimming tests were compared. Ten thoroughbred horses were subjected to different types of exercise tests on a track or in a pool, and the maximum heart rate during and the blood lactate concentration immediately after the exercise were examined. Serial exercise parameters (VLA2, VLA4, LA0, V150, V200, HRS, HRLA2, HRLA4) referred to as the indices related to the adaptation of cardiovascular or metabolic systems were computed using the relationships between these measurements and velocity during each test, and were analyzed by a multivariate procedure, i.e. the principal component analysis. The correlation diagram between the exercise parameters on the first two component axes in running were similar to that in swimming. When the exercise fitness in each horse was compared between running and swimming, three horses trained by short-term endurance exercise were statistically distinguished in both tests and differed as a group from the other horses. Therefore, it is thought that evaluation of the exercise fitness in swimming using the multivariate analysis is useful for predicting poor performing horses on a track.

Animals↗
PubMed1994

The validity of swimming training for two-year-old thoroughbreds.

To investigate the validity of swimming training, the following matters were considered: 1) changes in the performance capacity, 2) changes in the constitution and 3) frequency of locomotor diseases. These were evaluated during a training program including both conventional exercise on a track and swimming. In this study, 24 two-year-old thoroughbred horses were studied, and divided into the following three groups: Group A, trained by only running; Group B, trained by running plus a gradual increase in swimming; Group C, trained by running plus constant swimming. As a result of standardized exercise tests, only the intercepts of the 3 regression curves between the speed and the blood lactate concentration in Group B increased significantly as the training progressed. While the growth in height in Groups B and C were greater than in Group A, the increase in girth and weight in Groups B and C were smaller than in Group A. The percentages with locomotor diseases during this experiment in Groups A, B, and C were 62.5%, 12.5% and 25.0%, respectively, and there was a significant difference (p < 0.05) between Group A and Group B. As mentioned, it was suggested that a training program including swimming training is seen as being useful for improvement in performance capacity, since it can reduce locomotor diseases in young horses and allow for smooth progress in future training.

Animals↗
PubMed1994

[The effects of continuous interpleural vs. epidural infusion for postoperative pain relief following thoracotomy].

We studied whether continuous interpleural infusion of bupivacaine would be effective in alleviating pain after thoracotomy compared with effect of continuous epidural infusion of bupivacaine and buprenorphine. Twenty patients who had received thoracotomy and lobectomy were randomly divided into two groups to receive continuous interpleural infusion (IP group) of 0.5% bupivacaine at the rate of 5 ml.h-1 or continuous epidural infusion (E group) of 0.25% bupivacaine and 0.025 buprenorphine at the rate of 1 ml.h-1. The patients assessed their level of pain using a 100 mm visual analog scale (VAS) at rest and on coughing or changing the posture, verbal descriptor pain scale (VDPS), and times of supplemental analgesic. Assessment was performed at 7 points (mornings and evenings) for 3 postoperative days. In the evening of the day of surgery, VAS at rest in IP group was significantly higher than one in E group, but VASs at rest were similar in both groups from the first postoperative day to the third postoperative day. VAS on coughing or changing the posture in IP group was significantly higher than in E group in the evening of the day of surgery, and VASs on coughing or changing the posture in IP group were higher than in E group for 3 postoperative days. Supplemental analgesics were administered significantly more often than in E group in the evening of the first postoperative day. We conclude that continuous interpleural infusion does not give better analgesia than continuous epidural infusion after thoracotomy.

Adult↗
PubMed1994

[Psychological evaluation of patients by state-trait anxiety inventory in pain clinic].

In 84 outpatients who visited our pain clinic, we evaluated their anxiety before the first examination, using State-Trait Anxiety Inventory. State anxiety scores were high in all the patients regardless of their underlying disease. Trait anxiety scores in patients with chronic pain such as postherpetic neuralgia or cervic-shoulder-hand syndrome were higher than in patients with facial nerve palsy, sudden hearing loss or herpetic pain. This study indicates that psychosomatic management is mandatory for patients with chronic pain.

Adult↗
PubMed1994

[Changes in plasma concentrations of human hepatocyte growth factor before and after major intra-abdominal surgery under nitrous oxide-sevoflurane anesthesia].

The measurements of human hepatocyte growth factor (hHGF) in plasma and liver function tests were performed in 23 patients before and after major intra-abdominal surgery under nitrous oxide-sevoflurane anesthesia. Plasma concentrations of hHGF in 12 patients with normal liver function (Group 1) and in 11 patients with liver dysfunction (Group 2) were 0.34 +/- 0.07 and 0.44 +/- 0.12 ng.ml-1 (mean +/- SD) before the surgery, respectively. After the surgery, plasma concentration of hHGF remained unchanged in Group 1, but significantly increased to 0.61 +/- 0.32 ng.ml-1 in Group 2. Other routine laboratory data reflecting hepatic functions remained unchanged in both groups. These results suggest that liver damage during surgery and anesthesia occurs more likely in patients with liver dysfunction than in patients with normal liver function, and hHGF can be a more sensitive indicator of hepatic damage than conventional liver function tests.

Abdomen↗
PubMed1994

[Effects of repeated sevoflurane anesthesia on hepatic and renal function in a pediatric patient].

A 10-yr-old boy with an injured lower extremity received sevoflurane anesthesia 5 times within 40 days. Laboratory tests for hepatic and renal function i.e., serum transaminase (glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, gamma-glutamyl transpeptidase), serum cholinesterase, plasma protein, serum cholinesterase, serum bilirubine, serum lactic dehydrogenase, serum prothrombin time, blood urea nitrogen, serum creatinine, beta 2-microglobulin, N-acetyl-D-glucosamidase and 24 hr-creatinine clearance remained within normal ranges throughout his perioperative period. Repeated sevoflurane anesthesia did not exert any adverse effect on hepatic and renal function in this patient.

Anesthesia, Inhalation↗
PubMed1994

[Effect of indomethacin as an adjunct to postoperative pain relief by continuous epidural infusion of bupivacaine and buprenorphine].

We examined the analgesic effects of indomethacin as an adjunct to postoperative epidural analgesia in 40 patients who underwent upper abdominal surgery. Twenty patients in control group were epidurally given 0.1 mg of buprenorphine in 8 ml of 0.25% bupivacaine immediately after surgery and subsequently infused 15 micrograms buprenorphine in 1 ml of 0.25% bupivacaine at a rate of 1 ml.h-1 for 48 h. The remaining 20 patients were rectally given 50 mg of indomethacin in addition to the same epidural method described above. The patients who did not need additional narcotics in the control and indomethacin groups were 45% and 80%, respectively (P < 0.05). In upper abdominal surgery, postoperative pain relief by epidural buprenorphine and bupivacaine plus rectal indomethacin was more effective than that by epidural buprenorphine and bupivacaine.

Abdomen↗
PubMed1994

[Usefulness of continuous intra-arterial blood gas monitoring in a patient undergoing tracheal transection and reconstruction].

Usefulness of a new continuous intra-arterial blood gas monitoring system (PB3300, Puritan-Bennett, Carlsbad, California) was evaluated in a patient with tracheal cancer who was undergoing tracheal transection and reconstruction. The PB3300 detected continuous changes in pH, PaCO2, and PaO2 during the surgical intervention and provided reliable information to take appropriate therapeutic measures. PB3300 was superior to pulse oximetry because the latter can not detect changes in PaO2 more than 100 mmHg accompanying pulmonary dysfunction caused by surgical procedures. We conclude that the PB3300 is a useful monitor when used during anesthetic management of the patient who needs frequent arterial blood gas analyses.

Aged↗
PubMed1994

[Effects of intravenous and intramuscular atropine on bradycardia during spinal anesthesia].

The effects of intravenous and intramuscular atropine on pulse rate have been studied in 40 patients undergoing gynecological surgery. Intramuscular atropine 0.5 mg was administered 30 min before induction of spinal anesthesia in 20 patients (i.m. group). Intravenous atropine 0.5 mg was administered immediately after induction of spinal anesthesia in 20 patients (i.v. group). Decrease in heart rate after spinal block was significantly less in i.v. group than in i.m. group. Although no one in i.v. group was given an additional atropine, 10% of the patients in i.m. group was given an additional atropine for bradycardia. Authors conclude that intravenous atropine has more significant effect on prevention of bradycardia during spinal anesthesia compared with intramuscular atropine.

Anesthesia, Spinal↗