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Biomedical subjects

R Ogawa

Publications and source records attributed to R Ogawa.

At least 19 recordsLinked to original sources
PubMed2000

Treatment of intractable autoimmune diseases in MRL/lpr mice using a new strategy for allogeneic bone marrow transplantation.

A new bone marrow transplantation (BMT) method for treating severe autoimmune diseases in chimeric resistant MRL/lpr mice is presented. The method consists of fractionated irradiation (5.5 Gy x 2), followed by portal venous (PV) injection of whole bone marrow cells (BMCs) from allogeneic normal C57BL/6 (B6) mice and intravenous (IV) injection of whole B6 BMCs 5 days after the PV injection (abbreviated as 5.5 Gy x 2 + PV + IV). All recipients survived more than 1 year after this treatment (more than 64 weeks after birth). Abnormal T cells (Thy1.2(+)/B220(+)/CD3(+)/CD4(-)/CD8(-)) present in MRL/lpr mice before the treatment disappear, and hematolymphoid cells are reconstituted with donor-derived cells. The treated mice are free from autoimmune diseases. Levels of autoantibodies (IgG/IgM anti-ssDNA antibodies and IgG/IgM rheumatoid factors) decrease to normal levels. Successful cooperation is achieved among T cells, B cells, and antigen-presenting cells (APCs) of the treated MRL/lpr mice when evaluated by in vitro anti-SRBC responses. Newly developed T cells are tolerant to both donor (B6)-type and host (MRL/lpr)-type major histocompatibility complex (MHC) determinants. These findings clearly indicate that severe autoimmune diseases in MRL/lpr mice are completely ameliorated by the treatment without recourse to immunosuppressants, and that the treated MRL/lpr mice show normal immune functions, strongly suggesting that this strategy would be applicable to humans. (Blood. 2000;95:1862-1868)

Animals↗
PubMed2000

Minor cardiac troponin T release in patients undergoing coronary artery bypass graft surgery on a beating heart.

OBJECTIVES: To determine whether and to what extent coronary artery bypass graft (CABG) surgery without extracorporeal circulation is associated with cardiac troponin T (TnT) release. DESIGN: Prospective study. SETTING: A single university hospital. PARTICIPANTS: Twenty-three patients scheduled for minimally invasive CABG surgery. Sixteen patients received one coronary anastomosis, and seven received two. INTERVENTIONS: TnT and creatine kinase-MB (CK-MB) levels were determined immediately before induction of anesthesia (baseline) and at 0, 12, and 24 hours after surgery. Hemodynamic measurements were made, and 5-lead electrocardiograms with continuous automated ST-segment trends were analyzed. MEASUREMENTS AND MAIN RESULTS: All patients had a good cardiac outcome. Median cumulative coronary artery occlusion time was 27 minutes (range, 10 to 49 minutes). TnT levels were undetectable in 91.3% of patients at baseline when a detection limit of 0.01 ng/mL was employed. TnT and CK-MB showed significant elevations at 12 and 24 hours versus baseline. Postoperatively, TnT was detectable in 91.3% of patients, and 17.4% suffered minor myocardial damage, as evidenced by an abnormal increase in TnT greater than 0.2 ng/mL, excluding those exhibiting myocardial infarction. ST segment changes developed in seven patients, persisting for 13.0 minutes (range, 9.5 to 15.8 minutes) and disappearing immediately after coronary artery clamp release. There were no significant correlations between cumulative coronary occlusion time and peak TnT or CK-MB levels. CONCLUSIONS: TnT was detected after surgery in most patients, and significant TnT levels indicative of myocardial injury (>0.2 ng/mL) were detected in only 17% of patients, probably as a result of brief periods of coronary artery occlusion.

Adult↗
PubMed2000

Patients with diabetic neuropathy are at risk of a greater intraoperative reduction in core temperature.

BACKGROUND: Core hypothermia develops after the induction of general anesthesia, but intraoperative vasoconstriction usually prevents its progression. However, diabetes mellitus is often associated with autonomic neuropathy, which leads to abnormal peripheral neurovascular function. Accordingly, we tested the hypothesis that diabetic patients experience a greater reduction in core temperature during general anesthesia than nondiabetic patients. METHODS: We studied 36 nondiabetic patients (control group) and 27 diabetic patients (diabetic group) undergoing elective abdominal surgery. Both groups were divided into young (< 60 yr) and older age (>/= 60 yr) groups. Standard noninvasive autonomic tests (heart rate variation at deep periodical breathing, Valsalva maneuver, and head-up tilt) were carried out for each patient. The relation between the results of these tests of autonomic function and the tympanic membrane temperature during general anesthesia was assessed in relation to peripheral vasoconstriction. RESULTS: Thirteen patients in the diabetic group showed abnormal responses to two or more of the basal autonomic function tests (patients with autonomic dysfunction). Changes in core temperature among the groups were similar at 90 min after the induction of anesthesia. However, the core temperature of the diabetic patients with autonomic dysfunction was lower from 120 min (35.1 degrees C) onward compared with the young or older nondiabetic patients and the diabetic patients with normal autonomic function. Peripheral vasoconstriction, evaluated using the forearm-fingertip skin surface temperature gradient, was delayed in patients with autonomic dysfunction compared with the others. CONCLUSIONS: The current results indicate that diabetic autonomic neuropathy is associated with more severe intraoperative hypothermia. We postulate that diabetic patients become more hypothermic because their peripheral neuropathy delays the onset of thermoregulatory vasoconstriction and reduces its efficacy once triggered. These patients may therefore fail to develop a normal core temperature plateau.

Abdomen↗
PubMed2000

Cervical curvature after laminoplasty for spondylotic myelopathy--involvement of yellow ligament, semispinalis cervicis muscle, and nuchal ligament.

To assess the consequences of cervical laminoplasty on postoperative lordosis, a retrospective radiographic analysis of 31 patients undergoing laminoplasty for spondylotic myelopathy was completed. Special attention was paid to lordotic changes occurring at each level over more than 2 years. Preoperative lordosis remained unchanged with the patients wearing a cervical orthosis 1 week postoperatively. However the lordosis subsequently demonstrated a significant decrease in 87% of patients over an average of 3.1 years. Lordotic alignment at C2-C3 and C6-C7 before surgery significantly decreased in 81% and 58% of patients 1 week postoperatively, and 84% and 81% at last follow up, respectively, while lordotic alignment at other levels pre- and postoperatively did not significantly change. Loss of lordotic alignment was largely attributed to detachment of semispinalis cervicis muscle on C2 and nuchal ligament on C6/C7 with a posterior approach and/or section of yellow ligament at C2-C3.

Adult↗
PubMed2000

The effect of previous administration of nizatidine on the neuromuscular effects of vecuronium and the effect of nizatidine on gastric secretion.

Nizatidine, a new H2-receptor antagonist, has been reported to inhibit acetylcholinesterase activity. This could lead to an interaction with neuromuscular blocking drugs. This study examined the effects of nizatidine on the actions of vecuronium. Oral nizatidine has been reported to be an effective protective agent against acid aspiration syndrome, and we reevaluated this effect. The control group (n = 10) received a placebo with water 50 ml and the nizatidine group (n = 10) received nizatidine 300 mg with water 50 ml two hours before arrival in the operating room. Gastric contents were aspirated and the volume and pH measured before induction of anaesthesia. Anaesthesia was induced in all patients with thiopentone 5 mg/kg and 1.5% isoflurane in 98.5% oxygen followed by vecuronium 0.1 mg/kg. Vecuronium onset time and duration time 25 (time from injection until recovery of 25% of vaseline twitch amplitude) were obtained using electromyography. There were no significant differences between the two groups in vecuronium onset time or duration time 25. Gastric fluid volume was greater and gastric pH was lower in the control group than in the nizatidine group. 70% of the control group and none of the nizatidine group (P < 0.005) had a gastric content pH < 2.5 or volume > 25 ml.

Elective Surgical Procedures↗
PubMed2000

Intraventricular aneurysms--three case reports.

Three rare cases of purely intraventricular aneurysms are described, including a unique aneurysm in the fourth ventricle. A 30-year-old female, a 47-year-old male, and an 11-year-old girl presented with disturbance of consciousness due to massive intraventricular hemorrhage. Digital subtraction angiography revealed an idiopathic peripheral aneurysm in the fourth ventricle in the first patient, and aneurysms in the lateral ventricle associated with moyamoya disease in the latter two patients. The former two aneurysms were treated surgically and histologically confirmed to be pseudoaneurysms. The latter aneurysm disappeared spontaneously within 2 months after onset. The aneurysm in the lateral ventricle was resected via a parietal corticotomy with stereotactic insertion of an 8-Fr silicone tube to guide the approach route. This method was very useful because computerized neuronavigation was not available. The aneurysm in the fourth ventricle was resected via a midline suboccipital approach with C-1 laminectomy. Conservative treatment is usually recommended initially for patients with intraventricular aneurysm because spontaneous cure often occurs. We recommend direct surgery if the size of the aneurysm remains unchanged, because the risk of surgery has decreased recently owing to new techniques for neuronavigation.

Adult↗
PubMed2000

Clinical and pathologic characteristics of lumbar disk herniation in the elderly.

The clinical and pathologic characteristics of lumbar disk herniation in 23 elderly patients (15 men and 8 women) who required surgical treatment were investigated. Average age at surgery was 67.3 years, and average follow-up was 23 months. Preoperatively, the predominant symptom was severe unilateral leg pain, and 13 patients were nonambulatory because of leg pain. Operative treatment included wide laminectomy in 8, hemilaminectomy in 3, fenestration in 10, and osteoplastic laminectomy in 2 patients. Four (17%) patients had disk herniation at the L2-L3 or L3-L4 level. Sequestered herniation with or without migration was observed in 15 (65%) patients. Of 14 sequestered disk fragments examined histologically, 8 (57%) specimens contained cartilaginous or bony end plate with anulus fibrosus or nucleus pulposus. Postoperatively, results were rated as excellent in 11 patients and good in 12; no patient was rated as fair or poor. Severe leg pain affecting activities of daily life is a predominant symptom of disk herniation in the elderly. For patients in whom conservative treatment has failed, operative treatment should be considered. In lumbar disk herniation in the elderly, the incidence of cephalad and lateral herniation is higher than in younger patients. In addition, sequestered and migrated herniations including end plate are frequent.

Activities of Daily Living↗
PubMed1999

A new planar multielectrode array for extracellular recording: application to hippocampal acute slice.

The present paper describes a new planar multielectrode array (the MED probe) and its electronics (the MED system) which perform electrophysiological studies on acute hippocampal slices. The MED probe has 64 planar microelectrodes, is covered with a non-toxic, uniform insulation layer, and is further coated with polyethylenimine and serum. The MED probe is shown to be appropriate for both stimulation and recording. In particular, multi-channel recordings of field EPSPs obtained by stimulating with a pair of planar microelectrodes were established for rat hippocampal acute slices. The recordings were stable for 6 h. Finally a spatial distribution of long-term potentiation was studied using the MED system.

Animals↗
PubMed1999

External iliac artery occlusion in posterior spinal surgery.

STUDY DESIGN: Report of a case of external iliac artery occlusion occurring as a rare complication of lumbar posterior spinal surgery. OBJECTIVE: To clarify the cause of this rare complication and recommend methods for preventing its recurrence. SUMMARY OF BACKGROUND DATA: Several cases of central retinal artery occlusion after posterior spinal surgery have been reported, but there has been no reported case of external iliac artery occlusion after posterior spinal surgery. METHODS: A 65-year-old woman who had a 32-year history of systemic lupus erythematosus underwent posterior decompression and spinal fusion for degenerative scoliosis. She was supported on a Hall frame during the operation. Three hours after surgery, paralysis and sensory impairment of the left leg and cyanosis of the toes of the left foot were noted. The popliteal, dorsalis pedis, and posterior tibial pulses were not palpable. Angiography showed complete occlusion of the external iliac artery, and emergency removal of the thrombus was performed. RESULTS: One year later, neurologic symptoms were absent, and the leg vessels were normal. CONCLUSIONS: Prolonged direct pressure on the inguinal region during posterior spinal surgery on a Hall frame may cause external iliac artery occlusion. Early recognition and adequate treatment can prevent serious sequelae.

Aged↗
PubMed1999

Bilateral optic neuritis in a child diagnosed with Gd-enhanced MR imaging using fat-suppression technique.

A 4-year-old boy developed bilateral optic neuritis. Although precise neuro-ophthalmological evaluation was difficult, the diagnosis was made with gadolinium-enhanced MR imaging using fat-suppression technique in the initial stage of the disease. Enhancement and enlargement of the intraorbital and intracanalicular optic nerve were demonstrated bilaterally as well as protrusion of the optic nerve head. The disease responded dramatically to intravenous steroid therapy. The etiologies in children usually differ from those in adolescent and adult patients.

Adipose Tissue↗
PubMed1999

Medical check of competitive canoeists.

We gave a sports injury questionnaire survey to 821 active canoeists, members of the Japan Canoe Association (JCA), and performed a medical check of 63 top competitive JCA canoeists, including physical and laboratory tests and radiographic examinations of the chest, spine, shoulder, elbow, and wrist joints. Completed questionnaires were returned by 417 canoeists, whose reported racing styles were: kayak, 324; Canadian canoe, 71; slalom, 13; and not specified, 9. Of the 417 respondents, 94 canoeists (22. 5%) reported that they experienced lumbago; 20.9% experienced shoulder pain; 3.8%, elbow pain; and 10.8%, wrist pain. On medical examinations, lumbago was found to be mainly of myofascial origin or due to spondylolysis. Impingement syndrome was also observed in 4 canoeists with shoulder problems. The competitive canoeists had low blood pressure, and some had bradycardia. On laboratory examinations, serum hemoglobulin, hematocrit, high-density lipoprotein cholesterol (HDL-CHO), creatine phosphokinase (CK), and creatine (CRTN) in the top competitive canoeists showed high values in comparison with those of an age-matched control group. However, low serum total cholesterol (TP) values were observed in the top competitive canoeists.

Adolescent↗
PubMed1999

Effects of propofol anesthesia on cognitive recovery of patients undergoing electroconvulsive therapy.

The effects of different doses of propofol on post-electroconvulsive therapy (ECT) cognitive recovery were evaluated together with the effects on seizure duration and hemodynamic changes during ECT in 15 depressive patients. Propofol attenuated the increase in arterial blood pressure and heart rate in a dose-dependent manner compared with thiamylal. Propofol showed a clinically significant anticonvulsant effect during ECT in a dose-dependent manner. There were no significant differences among the four different induction groups in the mean recovery time from anesthesia, however, a low dose of propofol suppressed the early recovery of cognitive function. For early cognitive recovery after ECT, a deep anesthetic level is necessary when the traditional ECT apparatus is used which produces sine curve wave stimuli.

Adult↗
PubMed1999

Prostaglandin E2 mediates activation of hypothalamic histamine by interleukin-1beta in rats.

The present study was designed to investigate the effects of peripheral interleukin-1beta (IL-1beta) on hypothalamic histamine (HA) systems. Intraperitoneal injection of IL-1beta increased the turnover rate of hypothalamic HA, which was assessed by accumulation of tele-methylhistamine after pargyline treatment. IL-1beta increased the activities of both histidine decarboxylase (HDC), an HA synthesizing enzyme, and HA-N-methyltransferase (HMT), an HA catabolizing enzyme. Pretreatment with indomethacin completely blocked the effects induced by IL-1beta on hypothalamic HA. Infusion of prostaglandin E2 (PGE2) into the third cerebroventricle increased the hypothalamic HA turnover rate, and simultaneously activated both HDC and HMT dose-dependently, but intravenous infusion of PGE2 had no effect on the dynamics of hypothalamic HA turnover. These results indicate that hypothalamic PGE2 activated by peripheral administration of IL-1beta, but not by peripheral PGE2, may enhance synthesis and release of hypothalamic HA by activation of HDC, and may facilitate degradation of extracellular histamine by activation of HMT.

Animals↗
PubMed1999

Effect of ebselen on contractile responses in perfused rabbit basilar artery.

OBJECTIVE: To evaluate the possible role of the antioxidant ebselen in the treatment of cerebral vasospasm, we examined the effects of ebselen on the vasoactive mechanisms induced by endothelin (ET)-1, oxyhemoglobin, and oxygen-derived radicals. METHODS: Isolated rabbit basilar arteries with intact endothelium were fixed in a perfusion system and perfused intraluminally. Contraction of the artery was detected as an increase in perfusion pressure. RESULTS: Ebselen, in a certain concentration range (3 x 10(-6) and 10(-5) mol/L), significantly reduced the contractile response to ET-1 (10(-10) to 10(-8) mol/L) but not the contraction induced by 40 mmol/L potassium. It reduced the contraction induced by 10(-4) mol/L 1,2-dioctanoyl-sn-glycerol, a protein kinase C activator. Addition of 10(-5) mol/L dithiothreitol, a sulfhydryl-reducing agent, partially reversed the inhibitory effects of ebselen on ET-1- and 1,2-dioctanoyl-sn-glycerol-induced contractions. Ebselen (10(-5) mol/L) as well as a combination of catalase (1000 units/mL) and superoxide dismutase (150 units/mL) inhibited the potentiating effects of oxyhemoglobin (10(-5) mol/L) on ET-1-induced contraction. Both ebselen and catalase inhibited the contractile response to hydroxyl radical generated by ferrous ion (10(-3) mol/L) plus hydrogen peroxide (10(-2) mol/L). Ebselen reduced the response to potassium when a high dose (3 x 10(-5) mol/L) was applied and failed to preserve contractility of the preparation after exposure to hydroxyl radical. CONCLUSION: Ebselen suppressed ET-1-induced contraction and synergetic interaction between oxyhemoglobin and ET-1, where free radical formation was involved. These effects may result from modification of the intracellular regulatory system including protein kinase C, as well as from protection against free radicals.

Animals↗