Biomedical subjects

H Imaizumi

Publications and source records attributed to H Imaizumi.

At least 19 recordsLinked to original sources

PubMed2006

Comparative study on osteoconductivity by synthetic octacalcium phosphate and sintered hydroxyapatite in rabbit bone marrow.

Octacalcium phosphate (OCP) is thought to be a precursor of the mineral crystals in biological apatite. Synthetic OCP has been shown to be converted into an apatite structure when implanted in murine calvarial bone, to enhance bone regeneration more than synthetic hydroxyapatite (HA), and to degrade faster than biodegradable beta-tricalcium phosphate. This study was designed to investigate whether OCP implantation enhances the formation and resorption of new bone (remodeling) concomitant with OCP degradation when implanted intramedullary in a rabbit femur for 12 weeks, compared to sintered HA ceramic. Histological and histomorphometric analyses using undecalcified specimens showed that the area of bone apposition was significantly higher on OCP than on HA between 2 and 3 weeks, whereas it subsequently became smaller on OCP than on HA. The area attacked by multinucleated giant cells, including tartrate-resistant acid phosphatase (TRAP)-positive cells, was significantly higher for OCP than for HA at 8 weeks. Radiography revealed resorption of OCP but not of HA. The results disclose some osteoconductive characteristics of synthetic OCP in the bone marrow space: (1) enhancement of bone regeneration at the initial bone apposition stage and (2) stimulation of resorption of the newly formed bone coupled with OCP biodegradation mediated by TRAP-positive osteoclast-like cells. These results suggest that synthetic OCP would be a more useful bone substitute than HA in implant applications where rapid bone formation and concomitant implant resorption are important considerations.

Acid Phosphatase↗

PubMed2004

Reductions in levels of bacterial superantigens/cannabinoids by plasma exchange in a patient with severe toxic shock syndrome.

Toxic shock syndrome is a rare but potentially fatal toxin-mediated febrile illness. We report a case of toxic shock syndrome complicated by life-threatening organ dysfunction with high toxin-1 and staphylococcus enterotoxin type A levels that were successfully reduced by early introduction of plasma exchanges. The report shows the time course of the concentrations of anandamide and 2-arachidonyl glyceride and confirms that early introduction of plasma exchange can result in a rapid reduction of circulating toxins and mediators in the treatment of life-threatening multiple organ dysfunction.

Adolescent↗

PubMed2004

Production and blood parameters of Holstein cows treated prepartum with sodium monensin or propylene glycol.

Forty-five multiparous Holstein cows were assigned to one of 3 treatments in a randomized complete block design. The objective was to evaluate the effects of sodium monensin (M) and propylene glycol (PPG) during the prepartum period on performance and metabolic parameters during the late dry and first 9 wk postpartum for cows receiving M postpartum. Treatments were: control (C), M in a controlled-release capsule to deliver 335 +/- 33 mg/d for approximately 100 d, and 300 mL/d of PPG drenched orally. Treatments started at 35 and 21 d prior to the expected date of calving for cows receiving M and PPG, respectively. To ensure that all treatments would be restricted to the prepartum period, C and PPG cows received a M controlled-release capsule in the first 24 h after calving. Prepartum propylene glycol administration increased concentrations of glucose and insulin, and decreased beta-hydroxybutyrate and nonesterified fatty acids in plasma prepartum. Milk production was similarly affected by treatments. However, prepartum M treated cows tended to produce more 3.5% fat-corrected milk compared with control, but similar to PPG. Milk fat content and yield tended to be greater for cows that received M prepartum than for C cows, while PPG cows were similar to M and C. Prepartum administration of M decreased milk protein content, but no effect was observed on protein yield.

3-Hydroxybutyric Acid↗

PubMed2003

Endoscopic mucosal resection in the management of gastric carcinoid tumors.

BACKGROUND AND STUDY AIMS: Gastric carcinoid tumors are a rare disease. Previously, total gastrectomy was regarded as the treatment of choice. However, differences in biological malignancy have recently led to the increased use of endoscopic mucosal resection (EMR) for treatment. We studied the outcome of EMR in patients with gastric carcinoids who were treated at our hospital and discuss the indications for endoscopic treatment. PATIENTS AND METHODS: Between 1986 and 1999 we carried out gastric mucosal resection in five patients with gastric carcinoid tumors. The procedure used for EMR was either strip biopsy or endoscopic aspiration mucosectomy. RESULTS: The carcinoid tumors measured 10 mm or less in four of the five patients. Two patients had type A gastritis, and all had hypergastrinemia. There was no evidence of recurrence during follow-up (range 6 - 66 months; mean 32.6 months). CONCLUSION: EMR is useful in the management of type 1 gastric carcinoids as classified by Rindi (hypergastrinemia; tumor diameter of 10 mm or less).

Adult↗

PubMed2001

Simultaneous measurement of anandamide and 2-arachidonoylglycerol by polymyxin B-selective adsorption and subsequent high-performance liquid chromatography analysis: increase in endogenous cannabinoids in the sera of patients with endotoxic shock.

Anandamide (ANA) and 2-arachidonoylglycerol (2-AG), two endogenous cannabinoids, can be generated by activated macrophages and platelets, respectively, in the context of endotoxic shock, and are proposed to play a crucial role in the induction of the shock-related hypotension. Taking advantage of our recently discovered function of polymyxin B (PMB) binding to ANA and 2-AG, we developed a new method for measuring ANA and 2-AG by applying PMB-immobilized beads to selectively adsorb them in biological fluids, instead of organic solvent extraction. The eluate from beads can be directly fractionated by reverse-phase high-performance liquid chromatography (HPLC), and the fractionations corresponding to authentic ANA and 2-AG are collected and derivatized with fluorogenic reagent and subsequently quantified by HPLC with fluorometric detection. The calibration graphs of ANA and 2-AG were linear over a range of 1 to 500 pmol/ml. The limits of detection for ANA and 2-AG were 20 and 50 fmol, respectively. Intraassay precision was 2.24-4.25 and 3.47-5.44%, and interassay was 4.05-6.14 and 4.92-7.28% for ANA and 2-AG, respectively. Using this method, we first determined a 4-fold and 3-fold higher level of ANA and 2-AG, respectively, in the sera of patients with endotoxic shock than in normal serum. This finding should help in elucidating the role of the endogenous cannabinoids in the hypotension of human endotoxic shock. This method is rapid, sensitive, and reliable for simultaneously quantifying ANA and 2-AG in biological fluids, and has potential for clinical usage.

Adsorption↗

PubMed2001

Correlation between plasma endotoxin, plasma cytokines, and plasminogen activator inhibitor-1 activities in septic patients.

The objective of this study was to evaluate the relation between the clinical and plasma parameters and the changes in plasma endotoxin activity with 2 hours of endotoxin-adsorbing therapy using polymyxin B (PMX). A total of 88 consecutive patients were admitted for PMX treatment of severe sepsis or septic organ failure. Standard supportive care was continued without alteration during PMX treatment. Endotoxin, tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), IL-10, and plasminogen activator inhibitor-1 (PAI-1) activities and clinical parameters were measured before, immediately after, and the day after PMX treatment. The mean APACHE II and III scores were 24.2 +/- 1.0 and 85.8 +/- 3.0, respectively. The 2-week survival rate was 51.1%. In survivors, TNFalpha, IL-6, IL-10, and PAI-1 activities were significantly decreased during the 2-hour PMX treatment, the following day, or both times. There was no significant change in the parameters, except for TNFalpha, after PMX in nonsurvivors. In the subgroup whose plasma endotoxin decreased more than 30%, IL-6, TNFalpha, and PAI-1 significantly decreased after 2 hours of PMX or the following day (or both), but all four parameters in nonsurvivors showed no significant change. Hence PMX adsorbed plasma endotoxins and contributed to reductions in plasma proinflammatory cytokine levels and to improved clinical parameters during the 2-hour treatment. Changes in these parameters correlated with changes in plasma endotoxin activity in survivors whose plasma endotoxin levels were adequately reduced.

APACHE↗

PubMed2001

One Case of Harada Disease Complicated by Acute Posterior Multifocal Placoid Pigment Epitheliopathy-like Recurrence in Both Eyes.

Background: We encountered a patient who developed serous retinal detachment in one eye first, subsequently showed multiple small subretinal punctated opacity looking like acute posterior multifocal placoid pigment epitheliopathy (APMPPE) in both eyes, and had repeated recurrence.Case: A 28-year-old female presented with serous retinal detachment accompanied by multifocal small subretinal white punctated opacity at the posterior pole of the fundus in the left eye. Fluorescein angiography (FAG) revealed many small punctated hypofluorescent lesions scattered all over the eye in the early stage and multiple subretinal spotty leakage of fluorescein, subretinal accumulation of dye, and leakage of fluorescein from the optic disc in the late stage. Indocyanine green angiography (ICG) revealed small punctated hypofluorescent lesions from the early to late stage in both eyes. The disease recurred five and a half months after, and there appeared many yellowish white round opaque parts and serous retinal detachment at the posterior pole in both eyes. FAG showed a reversal phenomenon of fluorescein in both eyes. On ICG many small punctated hypofluorescent lesions were noted and in the late stage insular faint hypofluorescence consistent with serous retinal detachment, light tissue stain and fluorescent leakage in the center of the hypofluorescent lesion were also found. The disease recurred three times thereafter. At present, about two years after the first medical examination, the fundus does not show any sunset glow-like fundus, and vision of 1.2 is maintained on the right and left.Conclusion: A rare case of Harada disease complicated with APMPPE-like recurrence is presented.

Journal Article↗

PubMed2001

Alkaline esophagitis evaluated by endoscopic ultrasound.

CASE REPORT: Two patients with corrosive esophagitis caused by alkaline household agents were examined with endoscopic ultrasound using a 20-MHz probe. In the first case, endoscopic ultrasound revealed circumferentially thickened mucosa and muscularis propria, and lack of differentiation between the mucosa and submucosa. However, esophageal stricture did not develop during 3 months of follow-up, suggesting that the deep lesion may have involved a narrow section of esophagus only. In the second case, a markedly thickened mucosa was seen, resulting in no sequelae. Endoscopic ultrasound offers a more accurate evaluation of the depth of the lesions in alkaline esophagitis compared to standard endoscopy or computed tomography. Longitudinal studies are needed to identify lesions at greatest risk for progression to stricture.

Adult↗

PubMed2001

[Perioperative management of life-threatening intra-abdominal bleeding with intra-aortic balloon occlusion catheter].

Intra-thoracic aortic clamping using an intra-aortic balloon occlusion catheter (IABOC) is employed for patients with life-threatening intra-abdominal and/or extra-abdominal bleeding in spite of massive transfusion. For perioperative management, we inserted an IABOC preoperatively into a 59-year-old man with life-threatening intra-abdominal bleeding from an abscess formed around his traumatically injured pancreas. We could perform a safe operation in which bleeding was controlled by intermittently occluding the IABOC and the patient was thus prevented from developing into severe hemorrhagic shock. We experienced a usefulness of IABOC for a patient with life-threatening intra-abdominal bleeding uncontrolled due to intra-abdominal adhesion during the perioperative period. However, organ dysfunctions caused by ischemia and reperfusion following intra-aortic balloon occlusion must be prevented by shortening the occlusion time through use of an intermittent method such as described above.

Anesthesia, General↗

PubMed2001

Case report: right subclavian artery pseudoaneurysm due to perforation of esophageal cancer.

A 51-year-old man presented with massive hematemesis. Perforation of upper esophageal cancer, which had already occurred at least six days earlier, progressed to upper mediastinitis. The mediastinitis contiguous to the right subclavian artery was considered to have caused a pseudoaneurysm. Rupture of the pseudoaneurysm into the esophagus resulted in massive hematemesis. Both enhanced computed tomography and angiography were diagnostic for the pseudoaneurysm. Transluminal endovascular stent-grafts placement was successful in preventing subsequent hemorrhage.

Aneurysm, False↗

PubMed2001

[Persistent left-sided superior vena cava diagnosed after flow-directed pulmonary artery catheterization; report of a case].

We describe a case of persistent left-sided superior vena cava discovered after insertion of a pulmonary artery (PA) catheter. The diagnosis was suggested by chest X-ray after PA catheter placement and was subsequently confirmed by an echocardiograph. A 68-year-old man was admitted to our ICU because of septic shock induced by MRSA enterocolitis. In order to monitor the hemodynamic state of the patient, a PA catheter was inserted through the left subclavian vein after placement of a central venous and flexible double lumen catheters through the right internal jugular and subclavian veins, respectively. A chest X-ray showed the PA catheter passing along the left border of the heart. An echocardiograph showed the PA catheter passing through the coronary sinus into the pulmonary artery. Anesthesiologists and intensivists should be aware of the occurrence of left-sided superior vena cava in order not to mistake catheters placed in it as being in the arterial circulation or malpositioned outside of the venous circulation.

Catheterization, Swan-Ganz↗

PubMed2000

Phrenic nerve conduction in infancy and early childhood.

Diaphragmatic action potentials (DAPs) were mapped on the thorax bilaterally in 16 neurologically normal infants and 8 boys aged 1 to 4 years during artificial ventilation after thoracic surgery. Transcutaneous stimulation was used to activate the phrenic nerve at the supraclavicular fossa at the end of an artificial inspiration. The DAPs were of positive polarity and were recorded on the ipsilateral anterolateral chest wall over the sixth to the eighth intercostal spaces, with a maximal peak at the seventh intercostal space. The DAP latencies gradually decreased from 6 to 8 ms at birth to about 5 ms at the age of 1 year, despite an increase of conduction distance. Statistical analyses revealed that DAP amplitude did not correlate with age. The latencies and amplitudes of the DAPs displayed little interside variation. The results are valuable not only as a reference for the diagnosis of patients with phrenic nerve palsy, but also as an indicator of the normal development of the phrenic nerve.

Action Potentials↗

PubMed2000

Sound propagation and speech transmission in a branching underground tunnel.

The characteristics of sound propagation and speech transmission along a tunnel with a "T" intersection were investigated. At receivers within sight of the sound source, low frequencies were mainly attenuated around the intersection than high frequencies. At receivers out of sight of the source, high frequencies were extensively attenuated. The overall pattern of sound attenuation along the different sections of tunnel, which was calculated by the conical beam method, agreed well with the measurements in this study. Numerical calculations of reflected and diffracted waves with minimum transmission paths in a two-dimensional plane showed that reflected waves were the primary contributors to sound fields out of sight of the source. The articulation scores measured at receivers within sight of the source were high, and most of the confusion concerned syllables that could easily be misheard, even if there were a high signal-to-noise ratio. The types of syllable confusions observed at the receivers out of sight of the source appeared to have been caused by the greater deterioration in speech signals along this part of the tunnel, especially at high frequencies. The evaluation by rapid speech transmission indices (RASTI) appeared to be overestimated at the receivers out of sight of the source. Taking into account the early decay times of impulsive sound and the calculation procedures used in RASTI, it is concluded that speech intelligibility may not have been evaluated correctly by RASTI.

Adult↗

PubMed2000

A giant intramural gastric hematoma successfully treated by transcatheter arterial embolization.

We describe a case of intramural gastric hematoma with hemorrhagic shock caused by the formation of a large hematoma. Computed tomographic and angiographic examinations confirmed the presence of active bleeding into the hematoma. Transcatheter arterial embolization (TAE) was performed for hemostasis. To our knowledge, although 21 cases of intramural gastric hematoma have been reported in the literature, this is apparently the first case treated by TAE. We conclude that TAE is a safe and effective treatment option for intramural gastric hematoma confirmed to be associated with active bleeding into the hematoma.

Aged↗

PubMed2000

[Cesarean section using a temporary IVC filter in a pregnant woman with several histories of deep vein thrombosis].

A 31-year-old pregnant woman with a history of several episodes of deep vein thrombosis was scheduled for Caesarian section. The patient had an increased risk of intraoperative pulmonary thromboembolism due to thrombi isolated from deep veins. This is because a thrombus can be formed easily in deep veins by the influence of hypercoagulability in the third trimester and by the disturbance of venous return due to the pressure of the enlarged pregnant uterus. A temporary IVC filter (Filtre Thery, France) was inserted preoperatively. The filter basket was set in the IVC cephalad from the left renal vein and caudad from the hepatic vein. The operation was completed without any trouble. Rehabilitation was safely initiated just after the surgery by insertion of the filter and then the filter was removed on the third postoperative day. We conclude that the preoperative insertion of a temporary IVC filter is a useful technique to prevent intraoperative pulmonary thromboembolism in a patient with a history of deep vein thrombosis.

Adult↗

PubMed2000

[One case of Harada disease complicated by acute posterior multifocal placoid pigment epitheliopathy-like recurrence in both eyes].

BACKGROUND: We encountered a patient who developed serous retinal detachment in one eye first, subsequently showed multiple small subretinal punctuated opacity looking like acute posterior multifocal placoid pigment epitheliopathy (APMPPE) in both eyes, and had repeated recurrence. CASE: A 28-year-old female presented with serous retinal detachment accompanied by multifocal small subretinal white punctuated opacity at the posterior pole of the fundus in the left eye. Fluorescein angiography (FAG) revealed many small punctuated hypofluorescent lesions scattered all over the eye in the early stage and multiple subretinal spotty leakage of fluorescein, subretinal accumulation of dye, and leakage of fluorescein from the optic disc in the late stage. Indocyanine green angiography (ICG) revealed small punctuated hypofluorescent lesions from the early to late stage in both eyes. The disease recurred five and a half months after, and there appeared many yellowish white round opaque parts and serous retinal detachment at the posterior pole in both eyes. FAG showed a reversal phenomenon of fluorescein in both eyes. On ICG many small punctuated hypofluorescent lesions were noted and in the late stage insular faint hypofluorescence consistent with serous retinal detachment, light tissue stain and fluorescent leakage in the center of the hypofluorescent lesion were also found. The disease recurred three times thereafter. At present, about two years after the first medical examination, the fundus does not show any sunset glow-like fundus, and vision of 1.2 is maintained on the right and left. CONCLUSION: A rare case of Harada disease complicated with APMPPE-like recurrence is presented.

Acute Disease↗

PubMed2000

[A case of anaphylaxic shock due to latex glove used on internal examination and on the probe of intrauterine echogram].

A 15 year old female with uterus bicornis bicollis was admitted for operation. She had a history of atopic dermatitis and allergy to buckwheat, raw egg and latex. Two months previously she had developed whole body flushing during dental treatment, and latex glove used by the dentist had been suspected as the cause. Prior to the operation she underwent internal examination and intrauterine echogram in which a latex glove was carelessly used by another gynecologist who had not confirmed her past history. After 30 minutes, dyspnea and urticaria without itching, appeared suddenly. Blood pressure decreased to 80/50 mmHg and heart rate increased to 120 beats.min-1. She was then transferred to our ICU. Methylprednisolone was administered intravenously for dyspnea and circulatory collapse. After 3 hours, the patient made an uneventful recovery. The increased plasma latex protein-specific IgE levels confirmed anaphylaxis to latex. The increasing incidence of potentially life-threatening allergic reactions to latex has caused mounting concern over recent years. We may suspect latex allergy when an anaphylaxic reaction or shock of unknown origin occurs. In hospitals, latex free products must be prepared for use with latex allergic patients and for protection of medical staff with this allergy.

Adolescent↗

PubMed1999

Tritium incorporation into functional materials by applying OT-for-OH exchange reaction.

In order to reveal (1) the behavior of the tritium-labeled hydroxyl group (i.e., OT group) and (2) the effect of temperature on the dissociation equilibrium of tritiated water, the OT-for-OH exchange reaction in a homogeneous system was observed (1) using ion-exchange resins and HTO water, and (2) using hydrogen oxides and HTO water. Consequently, the following four conclusions were obtained: (1) The OT-for-OH exchange reaction occurred between each anion-exchange resin (or each metal hydroxide) and HTO water. (2) The higher the temperature is, the smaller the activity of both anion-exchange resin and metal hydroxide will be, and the activity of cation-exchange resin is large when the temperature is high. (3) The larger the degree of crosslinking in each Biorad AG1 resin is, the lower the activity of the resin will be. (4) The exchange rate for the OT-for-OH exchange reaction is small when the electronegativity of the metal ion in the metal hydroxide is large.

Anion Exchange Resins↗