Search PubMed⌕ Search

Biomedical subjects

H Iwasaka

Publications and source records attributed to H Iwasaka.

At least 19 recordsLinked to original sources
PubMed2004

Olprinone improves diaphragmatic contractility and fatigability during abdominal sepsis in a rat model.

BACKGROUND: Respiratory failure with diaphragmatic fatigability is common in patients suffering sepsis or septic shock. However, the development and progress of diaphragmatic fatigability remains poorly understood, and no method has been established to treat fatigability. In this study, we hypothesize that neutrophil activation contributes to the development of diaphragmatic fatigability. We also sought to investigate whether a phosphodiesterase inhibitor, olprinone, improves diaphragmatic fatigability associated with abdominal sepsis and inhibits an increase in myeloperoxidase activity in diaphragmatic muscle. METHODS: Male Wistar rats were randomly assigned to a sham group, coecal legation perforation group (CLP), and a phosphodiesterase inhibitor (PDE) pretreated group. At 16 h after surgical procedure, the left hemidiaphragm was removed for the measurement of diaphragmatic contractility and fatigability. In addition, for the measurement of serial changes in myeloperoxidase activity, the right hemidiaphragm was also removed at 4, 8 or 16 h after the surgical procedure in each group. RESULTS: In a septic model involving rats, we observed that diaphragmatic muscles were fatigable and myeloperoxidase activity increased. We also demonstrated that intraperitoneal administration of olprinone improves diaphragmatic fatigability and inhibits an increase in myeloperoxidase activity induced by abdominal sepsis. CONCLUSION: Olprinone represents a potential therapy for cases of respiratory failure with diaphragmatic fatigability resulting from inhibition of neutrophil activation.

Abdomen↗
PubMed2003

Association between minor physical anomalies and lateral ventricular enlargement in childhood and adolescent onset schizophrenia.

OBJECTIVE: The primary purpose of this study was to investigate the association between morphological abnormalities of brain and minor physical anomalies (MPAs) in childhood and adolescent onset schizophrenia. METHOD: Twenty-seven patients who had been diagnosed with schizophrenia according to DSM-IV criteria before 18 years of age were included in the study. MPAs were evaluated with the modified version of Waldrop scale (WS) by Green et al. Morphological abnormalities of brain was evaluated with ventricular-brain ratio (VBR) by using cerebral magnetic resonance imaging (MRI) examination. RESULTS: A significant positive correlation was observed between WS scores and VBRs. CONCLUSION: This result indicates a relationship between MPAs and lateral ventricular enlargement, and supports neurodevelopmental etiology in childhood or adolescent onset schizophrenia.

Adolescent↗
PubMed2001

Flecainide reverses neuropathic pain and suppresses ectopic nerve discharge in rats.

We investigated effects of flecainide, a Class IC sodium channel blocker, in the rat chronic constrictive injury (CCI) and ectopic nerve discharge models. In the behavioral evaluation, 2, 6, and 12 mg/kg flecainide were intravenously given to the CCI model, and a dose-dependent analgesic effect was shown on both thermal hyperalgesia and tactile allodynia. In the electrophysiological evaluation using the ectopic nerve discharge model produced by saphenous neurectomy, i.v. administration of 2, 6, and 12 mg/kg flecainide suppressed spontaneous discharge at the peripheral nerve level in a dose-dependent fashion as with the behavioral evaluation, but flecainide did not affect nerve conduction at the dose of 12 mg/kg.

Action Potentials↗
PubMed2001

Neutrophilia and granulocyte colony-stimulating factor levels after cardiopulmonary bypass.

PURPOSE: The precise mechanism of neutrophilia after cardiac surgery is unknown. Granulocyte colony stimulating factor (G-CSF) can increase the number of leukocytes. The purpose of this study was to evaluate the relationship between serum G-CSF levels and peripheral blood leukocyte counts after cardiac surgery. METHODS: We prospectively studied 10 patients undergoing cardiac surgery (coronary artery bypass grafting) using cardiopulmonary bypass (CPB). Plasma G-CSF levels and neutrophil count were measured before induction of anaesthesia, at the end of surgery, and on the first postoperative day. These changes were compared with those in patients undergoing non-cardiac major surgery (control group). RESULTS: At the end of surgery, G-CSF levels increased (P < 0.01) in both groups, but were higher in the control than in the cardiac group (3,250 +/- 690 vs 194 +/- 29.5 pg ml(-1), respectively, mean +/- SEM, P < 0.01). On the first postoperative day, G-CSF levels were still high in both groups, and were still higher in the control (710 +/- 179 vs 122 +/- 19.9, respectively, P < 0.01). However, neutrophilia was greater in the cardiac group than in the control. G-CSF response correlated positively with neutrophilia in the control group (r = 0.656, P < 0.05) but not in the cardiac group. CONCLUSIONS: Our results indicate that changes in leukocyte count following cardiac surgery are unique to patients undergoing CPB. G-CSF plays an important role as the mediator of neutrophilia after non-cardiac surgery, but not after cardiac surgery with CPB.

Aged↗
PubMed2001

Tetra-butyl ammonium attenuates evoked release of acetylcholine from mouse hemidiaphragm preparation.

Tetra-butyl ammonium is a homologous member of mono-quaternary ammonium salts, and it has been reported to have a property of nondepolarizing neuromuscular relaxant. However, no neurochemical evidences exist that tetra-butyl ammonium may interfere with quantal release of acetylcholine from motor nerve terminals. In this study, using the neurochemical method, we investigated the effect of tetra-butyl ammonium on stimulation-evoked release of acetylcholine from mouse hemidiaphragm preparation. The preparation was loaded with [3H]choline (5 microCi/ml). Low concentrations of tetra-butyl ammonium (10(-5) M) had no effects. On the other hand, at concentrations of 4x10(-5) and 10(-4) M, this compound significantly reduced the [Ca2+]o-dependent release of acetylcholine from phrenic nerves. This finding indicates that tetra-butyl ammonium possesses a presynaptic inhibitory effect on acetylcholine release from the phrenic nerve terminal.

4-Aminopyridine↗
PubMed2001

Effects of zinc acetate on splenocytes of endotoxemic mice: enhanced immune response, reduced apoptosis, and increased expression of heat shock protein 70.

Immune function is markedly attenuated in endotoxemia. Zinc is involved in the regulation of cellular functions and maintenance of immune function, and its level in the serum is low in endotoxemia. We mainly investigated the effects of zinc acetate (ZA) on splenocytes in mice with endotoxemia. After we confirmed increased plasma zinc level by ZA treatment, C57BL/6 mice were randomly divided into four groups: 10 control mice received 500 microL saline solution as vehicle; 10 control mice received ZA at 3 mg/kg body weight; 20 endotoxemic mice received a 40 mg/kg lethal dose of lipopolysaccharide (LPS); 20 mice received ZA followed by LPS as the above dose. In vivo, we confirmed that ZA pretreatment did not significantly affect the plasma cytokine level in endotoxemic mice. In vitro, splenocytes from ZA-plus-LPS mice showed drastic effects, in that ZA abrogated LPS-induced suppression of cellular proliferation and production of interleukin-2 and interferon-gamma. The percentage of apoptotic splenocytes was significantly reduced in ZA-plus-LPS mice (23.4%) as compared with LPS mice (41.6%). Furthermore, the expression of HSP-70 mRNA in splenocytes was strongly enhanced in both ZA and ZA-plus-LPS mice, especially in the latter group. Finally, studies monitoring survival rates for 6 days showed that LPS caused 100% mortality while ZA-plus-LPS mice showed 75% survival. Our results suggest that zinc normalized the immune response and reduced apoptosis of splenocytes. These changes were probably caused by increased synthesis of HSP-70 by splenocytes, which might enhance survival of mice with LPS-induced endotoxemia.

Animals↗
PubMed2001

Analgesic effects of flecainide on postherpetic neuralgia.

Sodium channel blockers have been reported to be effective in relieving neuropathic pain. However, although intravenous lidocaine has proved to be effective, in some patients oral mexiletine fails to produce adequate pain relief. In this study, we investigated the analgesic effect of flecainide, a long-lasting antitachyarrhythmic drug, on postherpetic neuralgia. Twenty patients with postherpetic neuralgia received an intravenous infusion of flecainide and 15 (75%) of those who achieved pain relief subsequently received oral flecainide. The patients were assessed using a 100 mm visual analog scale 1 month after treatment. Significant improvement compared with the pretreatment reading was found. This study suggests that the action of flecainide in blocking the sodium channel is potent and long-lasting and that, like the intravenous formulation, the oral formulation has a stable analgesic effect on postherpetic neuralgia.

Aged↗
PubMed2001

[Anesthetic management of a patient with Cockayne's syndrome].

Cockayne's syndrome is a disease of childhood characterized by mental retardation and premature aging. An 11-year-old girl with Cockayne's syndrome underwent general anesthesia for acute appendicitis. Although we had expected the difficulty of intubation because of her small jaw with limited movement, we could visualize her vocal cord, and intubate easily. High peak airway pressure was needed to ventilate her lung after intubation suggesting decreased lung compliance for this syndrome. We have to consider anesthetic problems resulting not only from pediatric but also from geriatric anesthesia for the management of this syndrome.

Acute Disease↗
PubMed2000

Brain imaging in childhood- and adolescence-onset schizophrenia associated with obsessive-compulsive symptoms.

OBJECTIVE: Childhood- and adolescence-onset schizophrenic patients with obsessive-compulsive symptoms (OCS) constitute a specific subgroup of schizophrenia. We performed magnetic resonance imaging in this group seeking evidence of neurodevelopmental insults. METHOD: Thirty-two schizophrenic patients were compared with 19 controls. Schizophrenic subjects were divided into 15 patients with OCS (SOCS+ group; onset at 15.5 +/- 1.6 years) and 17 without OCS (SOCS- group; onset at 15.3 +/- 1.3 years). Areas of the hippocampus, frontal lobe, corpus callosum and putamen were analysed morphometrically. RESULTS: The left hippocampus was significantly smaller in the SOCS+ group than in the SOCS- and control groups. CONCLUSION: Reduced size of the left hippocampus in the SOCS+ group supports a neurodevelopmental etiology in this subgroup.

Adolescent↗
PubMed2000

Unwashed shed blood infusion causes deterioration in right ventricular function after coronary artery surgery.

We investigated right ventricular function after infusion of unwashed shed blood collected from mediastinal and chest tube drainage. Changes in thromboxane B2 (TXB2) and 6-keto-PGF1 alpha, which are stable metabolites of thromboxane A2 (TXA2) and prostacyclin respectively, were also investigated. The amount of infused shed blood was 484 +/- 76 ml (mean +/- SD). Right ventricular ejection fraction decreased rapidly after the infusion and did not return to its original level until 120 minutes later (P < 0.05). Mean pulmonary artery pressure rose after infusion of the shed blood (P < 0.05). The TXB2 level in the unwashed shed blood was about 20,000 times higher than the preoperative plasma level. The plasma TXB2 level at 30 minutes after the infusion was significantly elevated (P < 0.05), and at 120 minutes it had returned to the original level. Unwashed shed blood may contain vasoactive substances that induce the release of TXA2 and increase right ventricular afterload.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

[Anesthetic management of a child with Lenz dysplasia associated with panhypopituitarism].

We present a child with Lenz dysplasia associated with panhypopituitarism. Lenz dysplasia is characterized by small eyeball, small head, hydronephrosis, cleft lip and palate, and mental retardation. A 12 month-old boy with Lenz dysplasia was scheduled for plasty of the lip and basis of the nasal cavity under general anesthesia. We had to pay attention for airway management and hormone supplementation. Anesthesia was induced with sevoflurane and nitrous oxide in oxygen. Tracheal intubation was facilitated with vecuronium bromide. We had no difficulty in airway management. Since this patient could not release enough endogenous cortisol in response to the stress of surgery, we supplemented hydrocortisone after anesthesia induction. Urine output and serum electrolyte concentrations were carefully monitored during surgery because of the impaired ADH response. We encountered no complications in the anesthetic management of this patient.

Anesthesia, General↗
PubMed1997

A study of cognitive development and behavior problems in mentally retarded children.

Cognitive development in seventy-one mentally retarded children (19 autistic, 52 non-autistic; aged 7-19 years) from a school for handicapped children was studied, using Ohta's scale for evaluating cognitive development level based on language comprehension (Ohta's stage), and other developmental scales. Behavior problems were also examined. The present study reports on the utility of Ohta's stage in non-autistic children, and the relationship between cognitive development level and behavior problems in mentally retarded children. In non-autistic children, there were temporal correlations between Ohta's stage and other development scales (a standard developmental test, speech development, symbolic play development, imitation development), suggesting that in non-autistic children as well, Ohta's stage may serve well as a scale for cognitive development, and reflect symbolic representational functioning. In non-autistic children, most behavior problems in feeding, elimination and sleeping, hyperkinesis, hypokinesis, stereotyped behaviors, self-injurious behavior and licking were closely associated with cognitive development level, and were more often noted in children of lower cognitive development level rather than only in the severely mentally retarded children. Some behavior problems may often occur in the sensorimotor period and hardly occur in the symbolic representational period.

Adolescent↗
PubMed1997

Porphyromonas gingivalis fimbria-stimulated bone resorption is inhibited through binding of the fimbriae to fibronectin.

Our most recent study demonstrated that fibronectin is one of the Porphyromonas gingivalis fimbria-binding proteins. In this present study, we demonstrate with mouse embryonic calvarial cells that P. gingivalis fimbria-stimulated bone resorption is inhibited by human fibronectin. The fibronectin inhibition was dose and culture time dependent and was completely neutralized by antifibronectin antibody. The inhibitory action of fibronectin depended on fimbrial interaction with the heparin-binding and cell-attachment domains in the fibronectin structure.

Animals↗
PubMed1997

[Anesthetic management for a patient with pure autonomic failure].

Pure autonomic failure is characterized by orthostatic hypotension, sweating disorder, urinary incontinence, and syncope. A 64 year-old man with pure autonomia failure was scheduled for suprapubic prostatectomy. We monitoring direct arterial pressure and inserted pulmonary artery catheter prior to the induction of anesthesia. General anesthesia was induced with diazepam 10 mg, fentanyl 0.3 mg, and vecuronium 8 mg for tracheal intubation. Anesthesia was maintained with sevoflurane (0.2-1.5%), 60% nitrous oxide in oxygen supplemented with intermittent epidural anesthesia. During anesthesia, blood loss was immediately replaced with banked blood because autonomic failure could not compensate hypovolemia well. Epidural anesthesia in this patient was considered to cause less hypotension than in patients with normal autonomic function. Therefore, we think epidural anesthesia is a useful anesthesia method for patients with pure autonomic failure. The emergence from anesthesia was smooth and no complications were seen during the perioperative period.

Anesthesia, Epidural↗
PubMed1997

[Effects of loprinone hydrochloride on hemodynamics and respiratory oxygenation in patients after cardiac surgery].

Loprinone hydrochloride (Lop), a phosphodiesterase fraction III inhibitor and positive inotrope, was recently released in Japan. We evaluated its dose-related effects on hemodynamics and oxygenation as as well as on plasma levels of Lop in ten patients after cardiac surgery. Immediately after admission to the intensive care unit, baseline hemodynamics and arterial blood gas data were obtained; patients with inotropic support, were given 0.1, 0.2, 0.3 microgram.kg-1.min-1.lop over 1 hour incrementally, and additional data were obtained. CI increased significantly from baseline (2.1 +/- 0.3 l.min-1.m-2) to 3.2 +/- 0.8 at 0.3 microgram.kg-1.min-1. Systemic vascular resistance decreased significantly from baseline (2853 +/- 439 dynes.sec.cm-5.m-2) to 1554 +/- 440 at 0.3 micrograms. kg-1.min-1, and mean arterial pressure also decreased significantly from baseline. There were no significant changes in heart rate (HR), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), or PaO2.FIO2(-1) in patients over the period evaluated. Plasma levels of Lop rapidly increased to 27.8 ng.ml-1 (effective level; 20 ng.ml-1) at 0.3 microgram.kg-1.min-1. In this study, Lop was shown to effectively increase CI in patients after cardiac surgery with no significant changes in HR, CVP, PAOP or PaO2/FIO2. Thus, Lop has a beneficial effect in the treatment of patients with low cardiac output immediately after cardiac surgery.

Aged↗
PubMed1996

Continuous monitoring of ventilatory mechanics during one-lung ventilation.

OBJECTIVE: The Ultima SV respiratory monitor can be used to monitor the intraoperative effects of the lateral decubitus position and one-lung ventilation on ventilatory mechanics. METHODS: Eight patients with esophageal cancer who required one-lung ventilation for esophagectomy and reconstruction were enrolled in the study. We monitored pressure-volume or flow-rate-volume loops continuously throughout the operation. Respiratory parameters were evaluated closely during five conditions of ventilation: two-lung ventilation in the supine position, two-lung ventilation in the lateral decubitus position, dependent one-lung ventilation in the lateral decubitus position, nondependent one-lung ventilation in the lateral decubitus position, and dependent one-lung ventilation in the lateral decubitus position with the chest opened. Respiratory rate was controlled at 10 breaths/min, and tidal volume was kept constant (10 ml/kg) during surgery. RESULTS: Peak inspiratory pressure increased to 29.0 +/- 9.0 (mean +/- SD) cm H2O in the dependent one-lung in the lateral decubitus position with the chest opened (p < 0.01). Dynamic compliance decreased to 29.4 +/- 4.9 ml/cm H2O in the dependent one-lung in the lateral decubitus position with the chest opened (p < 0.01). The changing configuration of the loops also offered additional and instantaneous information during one-lung ventilation. CONCLUSIONS: One-lung ventilation caused several changes in the whole respiratory system (lung, thorax, and endotracheal tube). Continuous monitoring of flow-rate-volume or pressure-volume loops with in-line spirometry provided comprehensive information regarding parameters in one-lung ventilation.

Aged↗
PubMed1996

Respiratory mechanics and arterial blood gases during and after laparoscopic cholecystectomy.

PURPOSE: The purpose of this study was to assess the effects of increased intra-abdominal pressure due to CO2 insufflation on the mechanical characteristics of the respiratory system and arterial blood gases during and after laparoscopic cholecystectomy. METHODS: Respiratory mechanics and arterial blood gases were examined in 12 patients undergoing laparoscopic cholecystectomy with CO2 insufflation. Respiratory mechanics were continuously monitored with in-line spirometry. In the recovery room, PaCO2 was measured in this group at 30 min and compared with PaCO2s in 23 patients who had undergone open cholecystectomy retrospectively, to evaluate the effects of insufflation on CO2 elimination. RESULTS: Minute ventilation was decreased by about 500 ml.min-1 during abdominal insufflation. Dynamic lung compliance decreased from 49.6 +/- 4.7 to 30.7 +/- 2.3 (mean +/- SEM) ml.cmH2O-1 with abdominal insufflation (P < 0.005), and returned to 45.1 +/- 3.1 after the release of pneumoperitoneum. Peak inspiratory pressure increased from 15.9 +/- 0.9 to 18.9 +/- 1.0 cmH2O with abdominal insufflation (P < 0.05). Arterial blood gas determinations indicated a decrease in arterial pH, with CO2 retention during insufflation and in the recovery room (P < 0.05). PaCO2 of the laparoscopic patients was higher than that of the open patients in the recovery room. CONCLUSION: The results indicate that respiratory acidosis was caused during CO2 insufflation for laparoscopic cholecystectomy, that was due to (1) decreased compliance, (2) increased CO2 load and (3) insufficient ventilation. Accumulated CO2 during laparoscopic cholecystectomy increased PaCO2 level in the recovery room.

Adult↗