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Biomedical subjects

R Shimizu

Publications and source records attributed to R Shimizu.

At least 217 records · Page 12Linked to original sources
PubMed1993

[Evaluation of the efficacy of a leukocyte depletion filter].

We evaluated the efficacy of a leukocyte depletion filter (Pall RC 100) during operation. Clinically necessary blood was transfused to replace blood loss during the operation. Kinds of transfused blood and speed of transfusion were selected by clinical need. One leukocyte depletion filter was used at most for 4 units of transfused pack (200 ml). Blood samples were taken before and after the filtration to measure white blood cell (WBC), red blood cell (RBC), platelet and hematocrit. Blood samples before filtration and after filtration with white blood cell excluded, were examined by automated hematology analyzer (Coulter counter). White blood cell after filtration was counted by the hemacytometer method using Hauser chamber. The method of multiple linear regression was applied in order to estimate the removal rate of WBC and recovery rate of RBC. The independent variables were categorized in the following 3 sets: the age of transfused blood (day), duration of transfusion (min) and transfused volume (ml). Removal rates of WBC when 1, 2, 3 or 4 units were passed per filter, were 99.99% +/- 0.028%, 99.89% +/- 0.224%, 99.12% +/- 1.519% and 97.81% +/- 2. 866%, respectively. Removal rate of WBC when 4 units were passed per filter, was significantly lower compared with the rate when fewer units were passed. Recovery rates of RBC when 1, 2, 3, or 4 units were passed per filter, were over 99.5%, and there were no significant differences among 4 examined points. Only three variables, the age of transfused blood, duration of transfusion and transfused volume, showed a significant correlation with the removal rate of WBC.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1993

[Right ventricular perforation and cardiac tamponade caused by a central venous catheter].

A 5 year old girl with ASD was scheduled for open heart surgery. A central venous catheter was placed via the right infraclavicular vein after induction of anesthesia. Thirty minutes after insertion of the catheter, a decrease in arterial pressure and pulse pressure, an increase in heart rate and central venous pressure were observed. Cardiac tamponade was revealed by rapid opening of the chest. Gushing blood out of a hole in the right ventricular free wall was confirmed by pericardiotomy. The hemodynamics were stabilized by blood transfusion and surgical closure of the hole on the ventricle. This perforation was thought to be caused by careless insertion of a relatively stiff central venous catheter.

Cardiac Surgical Procedures↗
PubMed1993

[Sevoflurane anesthesia in a patient following renal transplantation].

A 29-year-old male after renal transplantation with aseptic necrosis of the head of the left femur was anesthetized with sevoflurane-nitrous oxide-oxygen for replacement surgery. Anesthesia was induced with N2O 4 l.min-1, O2 2 l.min-1, plus sevoflurane and maintained with N2O4 l.min-1, O2 2 l.min-1 and sevoflurane. Sevoflurane concentrations ranged from 1% to 4%. The serum inorganic fluoride showed the peak level of 38.4 microM.l-1 about 60 minutes after discontinuation of sevoflurane a decrease in serum inorganic fluoride was delayed. Urinary N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyl transpeptidase (gamma-GTP) and beta 2-microglobulin (beta 2-m) increased over five postoperative days. NAG and gamma-GTP returned to the preanesthetic level on the 6th postoperative day, but beta 2-m higher than the preanesthetic level lasted for 14 postoperative days. In conclusion, sevoflurane brought about little effect on the transplanted kidney in this patient.

Adult↗
PubMed1992

Comparison of structure of quinone redox site in the mitochondrial cytochrome-bc1 complex and photosystem II (QB site).

A series of nitrophenolic electron-transport inhibitors (2-substituted 4,6-dinitrophenols) of rat liver mitochondrial cytochrome-bc1 complex and of photosystem II (QB site) of spinach thylakoids was synthesized. The structure/inhibitory-activity relationship was examined to elucidate differences in the three-dimensional structure of the quinone redox site in the two systems. These inhibitors occupy the ubiquinone redox site of cytochrome-bc1 complex competitively with natural ubiquinol, probably at a Qo reaction center. The inhibitory activity tended to increase with the length of the 2-substituent, which may correspond to the isoprenoid side chain of ubiquinone and plastoquinone, increased in both experimental systems. However, the strict structural requirements of the 2-substituent for binding to the ubiquinone or plastoquinone redox site were not identical. The alkyl substituents with a branching structure at the alpha-position to the benzene ring were favorable for inhibition of the cytochrome-bc1 complex, but not of photosystem II. Molecular-orbital calculations indicated that the main chain of 2-substituents with an alpha-branching structure was almost perpendicular to the benzene-ring plane because of steric congestion between the alpha-methyl and phenolic OH groups. The main chain of 2-substituents without an alpha-branching structure was flexible. Molecular-orbital studies indicated that ubiquinol was most stable when the portion of the isoprenoid side chain adjacent to the quinol ring was perpendicular to the quinol-ring plane, because of steric congestion by the vicinal OH and methyl groups. The side chain of plastoquinol was flexible because of the lack of a vicinal methyl group. Thus, the difference in the inhibitory activities between the two systems seemed to reflect the difference in the configuration of the isoprenoid side chain of ubiquinone and plastoquinone. These results suggested that the quinone redox site of the cytochrome-bc1 complex may recognize the configuration of the side chain near the quinone ring in the strict sense, whereas that of photosystem II (QB site) may recognize it in a loose sense.

Animals↗
PubMed1992

Biological activities and quantitative structure-activity relationships of spiro[imidazolidine-4,4'(1'H)-quinazoline]-2,2',5(3'H)-triones as aldose reductase inhibitors.

A series of spiro[imidazolidine-4,4'(1'H)-quinazoline]- 2,2'5(3'H)-triones were prepared and tested for aldose reductase inhibitory activity. The 6'-halogenated derivatives were found to be highly potent in vitro inhibitors of male rabbit lens aldose reductase and in vivo inhibitors of polyol accumulation in the sciatic nerves of galactosemic rats. Of these, (4R)-6'-chloro-3'-methylspiro[imidazolidine-4,4'(1'H)-quinazoline] -2,2',5(3'H)-trione (67) showed the most potent in vitro and in vivo activities. An oral dose of 3 g/kg of compound 67 caused neither death nor behavioral abnormality in the preliminary acute toxicity study using mice and rats. Compound 67 was selected as a candidate for further evaluation. The quantitative structure-activity relationships in this series are also discussed.

Aldehyde Reductase↗
PubMed1992

Evaluation of plasma erythropoietin levels in normal adult dogs by in vivo bioassay using concentrated plasma.

Measurement of plasma erythropoietin level in normal dogs by in vivo bioassay has been considered to be impossible so far. In the present study, we successfully determined it by using concentrated plasma 60 times which allowed the lower limit to 2.7 mU/ml. This normal plasma erythropoietin level was the first to be determined as an in vivo bioactivity and was 9.14 +/- 7.81 mU/ml in 75 normal adult dogs. This value was sufficiently reliable in terms of accuracy of determination and considered to be meaningful as the low level in vivo bioactivity that hasn't been known to date. Furthermore, erythropoietin levels in normal plasma were within a certain lower range and showed neither difference in plasma erythropoietin level between males and females or among breeds nor correlation between erythropoietin and hemoglobin level.

Animals↗
PubMed1992

[Postoperative pain relief by continuous epidural infusion of bupivacaine and buprenorphine].

Continuous postoperative pain relief produced by epidural block with bupivacaine and buprenorphine was evaluated in 12 patients after thoracotomy, 19 patients after upper abdominal surgery, and 14 patients after lower abdominal surgery. Patients initially received 8 ml of 0.25% bupivacaine and 0.1 mg of buprenorphine at recovery room in operating theater and continuously received the mixture of 0.25% bupivacaine and 5 micrograms.ml-1 buprenorphine at a rate of 1 ml.h-1 using a portable pump. About fifty percent of the patients did not need additional narcotics during 48 postoperative hours. About ninety percent of the patients needed one additional narcotics during 48 postoperative hours. The authors conclude that epidural analgesia with the mixture of bupivacaine and buprenorphine produces satisfactory postoperative pain relief.

Abdomen↗
PubMed1992

[Changes in retinal blood flow volume in experimental retinal vein compression].

The authors quantitated the retinal blood flow volume during and immediately after experimental compression of the temporal retinal vein in 5 Macaca fuscata monkey eyes. The hydrogen clearance method was used to quantitate the retinal blood flow volume. After placing a microelectrode on the retinal surface, we measured the blood flow volume 4 times at a 15-minute interval. This value served as a baseline for the experiments. Next we compressed the temporal retinal vein near the disc with a 25-gauge needle with a rounded tip under guidance by an indirect ophthalmoscope. We measured the blood flow volume during compression. The compression was maintained for 3 minutes. Further blood flow determination was performed 7 minutes after release of compression and was repeated 4 times at a 15-minute interval. During compression of the temporal retinal vein, the retinal blood flow volume in the area served by the vein decreased by an average of 35%. The flow volume recovered rapidly and remained stable after release of compression. There was no reactive hyperemia. This model appears useful to elucidate the retinal circulation of branch retinal vein occlusion.

Animals↗
PubMed1992

[Continuous epidural infusion of bupivacaine and buprenorphine for postoperative pain relief].

The efficacy for postoperative analgesia and side-effect of combined epidural infusion of bupivacaine and buprenorphine in comparison with each of these drugs alone were evaluated in 150 patients. All patients received initially bupivacaine 8 ml and buprenorphine 0.1 mg. In a random order, epidural infusion of 5 micrograms.ml-1 buprenorphine 1 ml.h-1 (group A; n = 50), 0.25% bupivacaine 1 ml.h-1 (group B; n = 50), or a combination of the two drugs 1 ml.h-1 (group C; n = 50) was continued for 48 h by a portable disposable device. The analgesic efficacy in group C was superior to that in group A or group B. No significant difference in the incidence of side-effect was found among the three groups. We conclude that epidural analgesia with the combination of buprenorphine and bupivacaine is safe, and easy to manage, giving pain relief superior to that provided by each of these drugs alone.

Adult↗
PubMed1992

[Hemodynamics and serum nitroglycerin concentration during intraoperative use of nitroglycerin patches].

We investigated the effect of number of nitroglycerin (TNG) as patches, containing 5 mg of TNG per sheet, on hemodynamics in 29 adult patients undergoing elective surgery. Patients were randomly allocated to four groups according to the number of the sheets applied (0, 2, 5 and 10 sheets). Hemodynamics as well as plasma TNG concentration were measured at 4 points (just before and 30, 60 or 120 minutes after application of TNG patch) in each group (n > or = 6). Plasma TNG concentrations depended on the number of the sheets and increased until 120 min after the application. Mean arterial pressure decreased gradually and significantly after applying two sheets or more. However, no relation was observed between the plasma concentration of TNG and the decrease in mean arterial pressure. We conclude that induced hypotension can not be intensified by increasing the number of the sheets of TNG patch.

Administration, Cutaneous↗
PubMed1992

[Sevoflurane anesthesia for asthmatic patients: report of five cases].

We anesthetized five patients receiving antiasthmatics with sevoflurane-nitrous oxide-oxygen. Induction with sevoflurane inhalation was conducted uneventfully in all patients. Mild asthmatic attacks occurred in three patients during light anesthesia. The asthmatic attacks subsided with elevating the concentration of sevoflurane or the administration of aminophylline in two patients. In only one patient, inhalation therapy with salbutamol was required to treat an asthmatic attack during deep anesthesia. The results indicate that sevoflurane was a proper inhalation anesthetic for our asthmatic patients.

Aged↗
PubMed1992

[Blood flow in the optic nervehead following intravenous administration of calcium antagonist].

The authors quantitated the blood flow of the optic nervehead after intravenous administration of calcium antagonist. The hydrogen clearance method was used to measure the blood flow after placing an electrode sensor in the optic nervehead of 9 eyes of 5 Macaca fuscata monkeys, under general anesthesia by intravenous pentobarbital sodium. 5 micrograms/kg of nicardipine, a calcium antagonist, was rapidly injected into the femoral vein. Measurement of blood flow in the optic nervehead was started 5 minutes after injection until 90 minutes at intervals of 15 minutes. A dose of 2 micrograms/kg/min nicardipine was then administered intravenously for another 90 minutes. During the experiment, intraocular pressure was maintained at 15 mmHg under continuous monitoring of systemic blood pressure. The blood flow in the optic nervehead decreased to 83% 5 minutes after injection. It increased slowly and reached the initial value 50 minutes later. It reached 108% of the initial value 80 minutes after injection. During the additional infusion of nicardipine, the blood flow decreased slowly and reached 85% of the initial value. It is concluded that the blood flow in the optic nervehead changed depending on the method, quantity and duration after injection of intravenous calcium antagonist. The blood flow decreased immediately after administration. The main cause of this phenomenon was thought to be due to decrease of perfusion pressure secondary to decrease of systemic blood pressure.

Animals↗
PubMed1991

Prokinetic effect of AS-4370 on gastric emptying in healthy adults.

The effect of AS-4370 on gastric emptying was investigated in healthy adults using 99mTc-DTPA. Single doses of AS-4370 2.5, 5 or 10 mg or placebo were administered to 12 subjects in a controlled, double-blind, cross-over study. Tests were performed twice weekly in each subject. Thirty min after administration of test drug or placebo, each subject swallowed a bun and orange juice containing 200 microCi nuclide. The radioactivity of the gastric content was measured for 40 min and the activity of the residue was expressed as a percentage of count at the initiation of measurements. The percentage radioactivity, AUC and gastric emptying time fitted by a power exponential curve, were analyzed. No significant difference was observed between the three dose levels of AS-4370 and placebo in half emptying time. However, decreases in the percentage of radioactivity with time were noted; 5 mg at 10 to 16 min and 10 mg at 8 to 24 min after the start of recording. Lower AUCs after 5 mg and 10 mg compared to placebo were also found. The half emptying time was also shorter after 5 mg and 10 mg than placebo. There was no difference in these parameters between 2.5 mg and placebo. The results indicate that AS-4370 5 and 10 mg but not 2.5 mg accelerates gastric emptying in healthy adults.

Adult↗