Biomedical subjects

S Ohmura

Publications and source records attributed to S Ohmura.

At least 19 recordsLinked to original sources

PubMed2001

Aerosolized surfactant therapy for endotoxin-induced experimental acute respiratory distress syndrome in rats.

We have compared the effects of inhalation of aerosolized surfactant on experimental acute respiratory distress syndrome. Escherichia coli endotoxin (55 (SD 20) mg kg(-1)) was injected into the tracheas of 36 adult rats anaesthetized and mechanically ventilated with pure oxygen. When the Pa(O(2)) decreased to 11.3 (3.3) kPa, the animals were randomly subjected to inhalation of aerosolized modified natural surfactant (MNS) for 0 min (control group), 30, 60, and 120 min. In the control group, Pa(O(2)) remained below 12 kPa for 180 min. In the groups receiving inhalation of surfactant for 30 and 60 min, Pa(O(2)) increased but decreased soon after termination of the inhalation. In contrast, Pa(O(2)) of the group receiving inhalation of surfactant for 120 min continued to increase, reaching 52.1 (12.5) kPa at 180 min (P<0.05 vs control). Thus, we conclude that improvement in gas exchange as a result of inhalation of MNS depends on the duration of inhalation.

Aerosols↗

PubMed2001

Systemic toxicity and resuscitation in bupivacaine-, levobupivacaine-, or ropivacaine-infused rats.

We compared the systemic toxicity of bupivacaine, levobupivacaine, and ropivacaine in anesthetized rats. We also compared the ability to resuscitate rats after lethal doses of these local anesthetics. Bupivacaine, levobupivacaine, or ropivacaine was infused at a rate of 2 mg. kg(-1). min(-1) while electrocardiogram, electroencephalogram, and arterial pressure were continuously monitored. When asystole was recorded, drug infusion was stopped and a resuscitation sequence was begun. Epinephrine 0.01 mg/kg was administered at 1-min intervals while external cardiac compressions were applied. Resuscitation was considered successful when a systolic arterial pressure > or =100 mm Hg was achieved within 5 min. The cumulative doses of levobupivacaine and ropivacaine that produced seizures were similar and were larger than those of bupivacaine. The cumulative doses of levobupivacaine that produced dysrhythmias and asystole were smaller than the corresponding doses of ropivacaine, but they were larger than those of bupivacaine. The number of successful resuscitations did not differ among groups. However, a smaller dose of epinephrine was required in the Ropivacaine group than in the other groups. We conclude that the systemic toxicity of levobupivacaine is intermediate between that of ropivacaine and bupivacaine when administered at the same rate and that ropivacaine-induced cardiac arrest appears to be more susceptible to treatment than that induced by bupivacaine or levobupivacaine.

Adrenergic alpha-Agonists↗

PubMed2001

A novel function of extraerythrocytic hemoglobin: identification of globin as a stimulant of plasminogen activator biosynthesis in human fibroblasts.

Following wounding, the surrounding fibroblasts migrate towards the clotted blood in the wounded space to form granulation tissue resulting in wound repair. One of the most abundant proteins in the wound is hemoglobin (Hb). The aim of the present study was to examine the effect of Hb on fibroblasts in producing components of the plasminogen-plasmin system which play an important role in wound healing. Human Hb A0 added to cultures of human fibroblasts elicited a dose-dependent increase in fibrinolytic activity. ELISA demonstrated an increased fibrinolytic activity due to increased urokinase-type plasminogen activator (uPA). An increase in tissue-type PA was also detected, while the type-I PA inhibitor level remained unaffected. Globin showed a similar effect, while hemin and protoporphyrin IX exerted no effect. The influence of Hb was quenched when haptoglobin was added. Although northern blot analysis revealed no difference in uPA transcripts between stimulated and non-stimulated cells, immunoprecipitation experiments confirmed an increased uPA synthesis in Hb- and globin-treated cells, suggesting that enhanced expression is achieved through translational regulation. These findings suggest a potential role for globin in modulating cellular functions during the process of wound healing.

Cells, Cultured↗

PubMed2000

Does hyperthermia induce peritoneal damage in continuous hyperthermic peritoneal perfusion?

To investigate the mechanisms of the peritoneal damage induced by continuous hyperthermic peritoneal perfusion (CHPP), protein and fluid loss during and after CHPP and continuous normothermic peritoneal perfusion (CNPP) was studied. Sixteen patients with advanced gastric cancer underwent peritoneal perfusion therapy with saline solution containing 150 to 300 mg cisplatin and 30 to 60 mg mitomycin C for 60 minutes. The temperature in Douglas' pouch was maintained at 42.0 degrees C in the CHPP group (n = 9) and 37.0 degrees C in the CNPP group (n = 7) during perfusion. No statistical differences were found in patients' characteristics between the groups except the maximum temperature in Douglas' pouch during perfusion (41.6 degrees +/- 0.4 degrees C and 37.6 degrees +/- 0.4 degrees C in CHPP and CNPP groups, respectively, p < 0.05). The amount of protein lost into the perfusate was 0.35 +/- 0.22 g/kg body weight in the CHPP group and 0.37 +/- 0.19 g/kg in the CNPP group, showing no significant difference. On the day of surgery, there was no significant difference in the amount of protein and fluid lost through the abdominal drains between the CHPP group (27.9 +/- 24.6 mg/kg/hr and 0.94 +/- 0.63 ml/kg/hr, respectively) and the CNPP group (25.9 +/- 8.6 mg/kg/hr and 1.03 +/- 0.31 ml/kg/hr, respectively). We could not find any significant differences in postoperative protein and fluid loss between the groups on the following 3 days either. We conclude that the peritoneal damage by CHPP is not caused by the hyperthermia but by the peritoneal perfusion with saline solution containing anticancer drugs.

Chemotherapy, Cancer, Regional Perfusion↗

PubMed2000

Left-molar approach improves the laryngeal view in patients with difficult laryngoscopy.

BACKGROUND: The molar approach of laryngoscopy is reported to improve glottic view in sporadic cases of difficult laryngoscopy. The authors studied the effect of molar approaches and optimal external laryngeal manipulation (OELM) using the Macintosh blade. METHODS: A series of 1,015 adult patients who underwent general anesthesia and tracheal intubation was studied. Laryngoscopy was carried out using a Macintosh no. 3 or 4 standard blade. Three consecutive trials of direct laryngoscopy using the midline and left- and right-molar approaches were carried out under full muscle relaxation with optimal head and neck positioning. The best glottic views were recorded for each approach with and without OELM. RESULTS: Difficult laryngoscopy with a midline approach accounted for 6.5% (66 cases) before OELM and 1.97% (20 cases) after OELM. A left-molar approach with OELM further reduced difficult laryngoscopy to seven cases (P < 0.001 vs. midline approach with OELM); a right-molar approach with OELM reduced difficult laryngoscopy to 18 cases (P = 0.48). CONCLUSIONS: The left-molar approach with OELM improves the laryngeal view in patients with difficult laryngoscopy.

Adolescent↗

PubMed2000

[Perioperative management for total en bloc spondylectomy--the effects of preoperative embolization and hypotensive anesthesia].

We retrospectively evaluated the effects of preoperative embolization and hypotensive anesthesia on total en bloc spondylectomy (TES) for solitary spinal metastases. In ten patients (treatment group), feeding arteries of spinal metastases were embolized preoperatively and controlled hypotensive anesthesia was induced during operation. In other ten patients (control group), these treatments were not applied. Intraoperative blood loss as well as the amount of blood transfused in the treatment group were significantly lower than those in the control group. Moreover, postoperative platelet counts in the treatment group were significantly higher than those in the control group. These findings indicate that embolization of feeding arteries of metastases and hypotensive anesthesia decrease intraoperative blood loss and may prevent postoperative complications in TES.

Aged↗

PubMed1999

The influence of hypoxia and hyperoxia on the kinetics of propofol emulsion.

PURPOSE: To study the effect of hypoxia and hyperoxia on the pharmacokinetics of propofol emulsion, hepatic blood flow and arterial ketone body ratio in the rabbit. METHODS: Twenty four male rabbits were anesthetized with isoflurane (1.5-2%) in oxygen. After the surgical procedure, isoflurane administration was discontinued and intravenous propofol infusion (30 mg x kg(-1) x hr(-1)) was started. The infusion rate of propofol was maintained throughout the study. After an initial 90 min period of propofol infusion, rabbits were randomly allocated to one of three groups: hypoxia (F(I)O2 = 0.1), normoxia (F(I)O2 = 0.21), and hyperoxia (F(I)O2 = 1.0). Propofol infusion was continued under the allocated F(I)O2 for 60 min. Propofol concentrations in arterial blood, total body clearance of propofol, hepatic blood flow and arterial ketone body ratio were measured. RESULTS: The mean arterial propofol concentration at the end of infusion was higher in the hypoxia group (15.2 +/- 2.8 microg x mL(-1), mean +/- SD) than in the normoxia (7.4 +/- 1.7) and hyperoxia (8.0 +/- 1.9) groups (P < 0.05). Total body clearance of propofol, hepatic blood flow and arterial ketone body ratio were all reduced in the hypoxia group (P < 0.05). Total ketone body concentration in arterial blood increased in the hyperoxia group (P < 0.01). CONCLUSION: Hypoxia produced an accumulation of propofol in blood and reduced propofol clearance. These changes could result from decreased hepatic blood flow and low cellular energy charge in the liver. Hyperoxia, on the other hand, increased total ketone body in arterial blood.

Anesthetics, Intravenous↗

PubMed1999

A comparison of the effects of propofol and sevoflurane on the systemic toxicity of intravenous bupivacaine in rats.

UNLABELLED: We compared the effects of propofol and sevoflurane on bupivacaine-induced central nervous system and cardiovascular toxicity in rats. Thirty-four male Sprague-Dawley rats were anesthetized with 70% N2O/30% O2 plus the 50% effective dose (ED50) of propofol (propofol group, n = 12); 70% N2O/30% O2 plus ED50 of sevoflurane (sevoflurane group, n = 11); or 70% N2O/30% O2 (control group, n = 11). Bupivacaine was infused at a constant rate of 2 mg x kg(-1) x min(-1) while electrocardiogram, electroencephalogram, and invasive arterial pressure were continuously monitored. The cumulative doses of bupivacaine that induced dysrhythmias, seizures, and 50% reduction of heart rate were larger in the propofol and sevoflurane groups than in the control group. The cumulative dose of bupivacaine that induced a 50% reduction in the mean arterial blood pressure was larger in the propofol group than in the sevoflurane and control groups. The margin of safety, assessed by the time between the onset of dysrhythmias and 50% reduction of mean arterial blood pressure, was wider in the propofol group than in the sevoflurane group. We conclude that propofol and sevoflurane attenuate bupivacaine-induced dysrhythmias and seizures and that propofol has a wider margin of safety than sevoflurane. IMPLICATIONS: In anesthetized patients, dysrhythmias may be the only warning sign of intravascular injection of bupivacaine. Because propofol has a wider margin of safety than sevoflurane, life-threatening cardiovascular depression may be prevented by stopping the injection of bupivacaine at the onset of dysrhythmias during propofol anesthesia.

Anesthetics, Inhalation↗

PubMed1999

Dextran restores albumin-inhibited surface activity of pulmonary surfactant extract.

We examined the effect of dextran (molecular weight 71,000) in counteracting the surfactant inhibitory action of plasma albumin. The surface adsorption time of 0.5 mg/ml modified natural surfactant (MNS; porcine lung extract consisting of phospholipids and hydrophobic surfactant proteins) with 7.5 mg/ml albumin decreased from 681 to 143 s by addition of dextran at a concentration of 10 mg/ml (P < 0.01). The minimum surface tension of 2.0 mg/ml MNS with 30 mg/ml albumin decreased from over 21 mN/m to below 3 mN/m when dextran was added at a concentration of 10 mg/ml (P < 0.01). Surfactant-deficient newborn rabbits given 10 ml/kg of a liquid containing 2.0 mg/ml MNS with 30 mg/ml albumin had a mean tidal volume </=5 ml/kg after 5 min of mechanical ventilation, but, in those animals given the liquid containing 10 mg/ml dextran also, the volume was >13 ml/kg (P < 0.05). Although the underlying mechanism remains to be elucidated, we conclude that dextran restores the albumin-inhibited surface activity of MNS.

Adsorption↗

PubMed1999

[Use of personal computers by diplomats of anesthesiology in Japan].

Use of personal computers by diplomats of the Japanese Board of Anesthesiology working in Japanese university hospitals was investigated. Unsigned questionnaires were returned from 232 diplomats of 18 anesthesia departments. The age of responders ranged from twenties to sixties. Personal computer systems are used by 223 diplomats (96.1%), while nine (3.9%) do not use them. The computer systems used are: Apple Macintosh 77%, IBM compatible PC 21% and UNIX 2%. Although 197 diplomats have e-mail addresses, only 162 of them actually send and receive e-mails. Diplomats in fifties use e-mail most actively and those in sixties come second.

Adult↗

PubMed1998

[Comparison of transarterial technique and paresthesia technique of axillary brachial plexus block].

Axillary brachial plexus blocks were established in 40 patients using transarterial technique (n = 20) or paresthesia technique (n = 20). Sensory and motor blockades of nerves supplying the upper extremity were compared at 10, 20 and 30 minutes after the injection of local anesthetics (1.5% plain mepivacaine 40 ml). Sensory blockades of the radial nerve and axillary nerve were significantly higher with transarterial technique than paresthesia technique. The incidence of analgesia of the radial nerve at 30 min was 100% with transarterial technique and 70% with paresthesia technique. Sensory blockades of the other nerves and motor blockades of all nerves did not show any significant differences between the two techniques. Proximal and distal spreads of the local anesthetic-contrast medium mixture within the axillary neurovascular sheath were studied in 20 patients. No statistically significant difference was observed in the spread of contrast agent between the two techniques. Transarterial technique is a recommendable method for hand surgery and especially indicated for the surgery of the area supplied by the radial nerve.

Adult↗

PubMed1997

Degradation of the 74 kDa form of L-histidine decarboxylase via the ubiquitin-proteasome pathway in a rat basophilic/mast cell line (RBL-2H3).

L-Histidine decarboxylase (HDC) is a dimer consisting of two identical 53 kDa subunits. On the other hand, the size of HDC deduced from its cDNA sequence is around 74 kDa, indicating that the translated 74 kDa form of HDC is subjected to post-translational processing to generate the 53 kDa form. However, modification of the translated 74 kDa form of HDC in histamine-forming cells is unknown. Here we demonstrate that the 74 kDa form is translated in rat basophilic leukemia cells, followed by conversion to the 53 kDa form, and that the 74 kDa form is a short half-life protein because of the degradation mediated by the ubiquitin-proteasome pathway. Degradation of the 74 kDa form was stimulated in the presence of an ATP-generating system, accompanied by ubiquitination, and inhibited by specific proteasome inhibitors such as ZL3H and lactacystin. A significant amount of proteasome activity was detected in RBL-2H3 cells.

Adenosine Triphosphate↗

PubMed1997

Predicting difficult intubation with indirect laryngoscopy.

BACKGROUND: It is not always possible to predict when tracheal intubation will be difficult or impossible. The authors wanted to determine whether indirect laryngoscopy could identify patients in whom intubation was difficult. METHODS: Indirect laryngoscopy was done in 2,504 patients. The Wilson risk sum score and the modified Mallampati score were also studied in a different series of 3,680 patients for comparison. These predictive methods were compared according to three parameters: positive predictive value, sensitivity, and specificity. RESULTS: Of 6,184 patients studied, the trachea proved difficult to intubate in 82 (1.3%). Positive predictive value (31%) and specificity (98.4%) with indirect laryngoscopy were greater than the other two predictive methods (P < 0.01), whereas sensitivity with indirect laryngoscopy (69.2%) was greater than that of the Wilson risk sum score (55.4%) (P < 0.01). CONCLUSIONS: Although in 15% of patients indirect laryngoscopy could not be performed because of excessive gag reflex, indirect laryngoscopy can serve as an effective method to predict difficult intubation.

Adult↗

PubMed1997

Effects of surfactant proteins SP-B and SP-C on dynamic and static mechanics of immature lungs.

To investigate the effects of surfactant proteins B (SP-B) and C (SP-C) on lung mechanics, we compared tidal and static lung volumes of immature rabbits anesthetized with pentobarbital sodium and given reconstituted test surfactants (RTS). With a series of RTS having various SP-B concentrations (0-0.7%) but a fixed SP-C concentration (1.4%), both the tidal volume with 25-cmH2O insufflation pressure and the static volume deflated to 5-cmH2O airway pressure increased, significantly correlating with the SP-B concentration: the former increased from 6.5 to 26.0 ml/kg (mean), and the latter increased from 6.4 to 31.8 ml/kg. With another series of RTS having a fixed SP-B concentration (0.7%) but various SP-C concentrations (0-1.4%), the tidal volume increased from 5.1 to 24.8 ml/kg, significantly correlating with the SP-C concentration, whereas the static volume increased from 3.4 to 32.0 ml/kg, the ceiling value, in the presence of a minimal concentration of SP-C (0. 18%). In conclusion, certain doses of SP-B and SP-C were indispensable for optimizing dynamic lung mechanics; the static mechanics, however, required significantly less SP-C.

Animals↗

PubMed1997

[Lack of hyperglycemic rebound after insulinoma removal: two case reports].

Two cases of anesthetic management for insulinoma were reported. The first patient, a 54-year-old man, suffering from repeated episodes of fasting hypoglycemia was scheduled for removal of insulinoma developed in the pancreas under isoflurane-nitrous oxide anesthesia. Preanesthetic plasma glucose concentration was 57 mg.dl-1. Glucose was continuously administered intravenously to maintain plasma glucose around 150 mg.dl-1. The second patient, a 65-year-old man suffering from several episodes of fasting hypoglycemia was scheduled for removal of insulinoma in the pancreas under isoflurane-nitrous oxide anesthesia. Preanesthetic plasma glucose was 103 mg.dl-1. An artificial pancreas was used to maintain plasma glucose at 140 mg.dl-1. In these patients, hyperglycemic rebound was not observed after removal of the insulinoma, and their perioperative courses were uneventful. Although relatively low immunoreactive insulin levels might relate, fine management of fluid and metabolism during preoperative period was thought as one of the reasons that hyperglycemic rebound did not occur in these patients. For the safe management of the patients with insulinoma, we recommend to maintain plasma glucose at the levels of mild hyperglycemia to prevent hypoglycemic episodes until the end of the removal.

Aged↗

PubMed1995

Prostate-specific antigen activates single-chain urokinase-type plasminogen activator.

Prostate-specific antigen (PSA) increases in the plasma of patients with prostate cancer, and has therefore been used as a reliable tumor marker. It has been demonstrated that prostate cancer cells over-express urokinase-type plasminogen activator (uPA), which plays an important role in tumor invasion and metastasis. We found that PSA converts the single-chain proform of urokinase-type plasminogen activator (scuPA) to an active 2-chain form. The active 2-chain uPA generated from scuPA by PSA was measured by hydrolyzation of S-2444, a synthetic substrate for uPA. PSA activated scuPA time- and dose-dependently. SDS-PAGE analysis revealed that, after incubation with PSA, the intensity of the 55-kDa band of scuPA decreased concomitantly with increases in the intensity of the 2 bands at 33 kDa and 22 kDa. Amino-acid-sequence analysis indicated that PSA cleaved Lys158-Ile159, which corresponds with the site cleaved by plasmin. PSA did not enhance or impair the activity of the 2-chain form of uPA. These findings imply that PSA could be an initiator of the protease cascade involved in prostate-cancer invasion and metastasis.

Amino Acid Sequence↗

PubMed1993

Human glyoxalase I. cDNA cloning, expression, and sequence similarity to glyoxalase I from Pseudomonas putida.

Glyoxalase I (EC 4.4.1.5) catalyzes the transformation of methylglyoxal and glutathione to S-lactoylglutathione. We have isolated human cDNA clones encoding glyoxalase I from a phorbol myristate acetate-treated U937 cDNA library. This cDNA encodes a protein of 184 amino acids with a calculated M(r) of 20,719. The amino acid composition calculated from the deduced amino acid sequence agreed with that reported for glyoxalase I purified from human erythrocytes. The Escherichia coli cells carrying the expression vector of this cDNA acquired methylglyoxal resistance and the cell lysate showed the high activity of glyoxalase I. The amino acid sequence of human glyoxalase I exhibited 57% identity with Pseudomonas putida glyoxalase I at the C-terminal two-thirds, suggesting that the two enzymes may have originated from a common ancestor.

Amino Acid Sequence↗

PubMed1993

Displacement of lidocaine from the lung after bolus injection of bupivacaine.

The purpose of this study was to determine whether lidocaine was displaced from the lung after bolus injection of bupivacaine. Fourteen anesthetized rabbits were randomly assigned to either a bupivacaine or a control group. Lidocaine was infused at a rate of 10 mg.kg-1 x hr-1. After one hour of infusion, a bolus of bupivacaine (1 mg.kg-1) in normal saline (0.2 ml.kg-1) was injected into the central venous circulation in the bupivacaine group. The control group was injected with normal saline. After bolus injection, arterial blood samples were collected serially from an internal carotid artery at 1.2-sec intervals for 24 sec. The baseline concentration of lidocaine was 3.0 +/- 0.1 micrograms.ml-1 in the bupivacaine group and 3.2 +/- 0.1 micrograms.ml-1 in the control group (NS). Arterial concentrations of lidocaine increased to a maximum of 4.7 +/- 0.2 micrograms.ml-1 in the bupivacaine group (P = 0.0001). No increases were seen in the control group. These findings indicate that lidocaine was displaced from the lung into the blood after bolus injection of bupivacaine. The amount of lidocaine displaced during the first passage of bupivacaine through the lung was calculated to be 92.3 +/- 9.7 micrograms. It is concluded that lidocaine is displaced from the lung after bolus injection of bupivacaine.

Animals↗