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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 487 records · Page 27Linked to original sources
PubMed1997

[Relationship between distortion product otoacoustic emissions and pure tone thresholds in normal and hearing-impaired ears].

To establish clinical criteria for distortion product otoacoustic emissions (DPOAEs) in order to distinguish normal-hearing from hearing-impaired ears, DPOAEs were measured and evaluated in 325 normal and 291 cochlear-impaired human ears using an ILO92 Otoacoustic Emission Analyzer. The background noise level was too variational in each individual ear to ignore in DPOAE measurements. Therefore, the value of the difference between the DPOAE amplitude and the background noise level (DPOAE noise) was calculated and compared with the pure tone threshold at 1 kHz, 2 kHz and 4 kHz. It was difficult, however, to precisely separate normal-hearing and hearing impaired ears with DPOAE noise values because many normal ears presented small amplitudes of DPOAEs and some impaired ears showed high amplitudes. Therefore, cumulative distributions of sensitivity (normal hearing ears identified as normal hearing) and specificity (hearing impaired ears identified as hearing impaired) were constructed and used to calculate a cut off point for DPOAE-noise in order to separate normal hearing from hearing impaired ears. It is considered that the cut-off points (DPOAE noise values of 7.3 dB at 1 kHz, 10.3 dB at 2 kHz and 16.1 dB at 4 kHz) at which the false alarm rates (1 specificity: the rate of hearing impaired ears incorrectly identified as normal hearing) correspond to 5% can be useful for clinical evaluation of DPOAEs.

Adolescent↗
PubMed1997

[The effects of a fimbria-fornix lesion on distance discrimination in rats].

In order to study the role of hippocampus in spatial learning, fimbria-fornix (FF) lesioned and control rats, eight each, were trained for a distance discrimination task in a rectangular test box (120 x 60 x 35 cm). A rat was placed in a start box at one of the corners of the test box, and then released to choose the bottle that contained food reward. Two bottles, at the distance of 50 cm, were placed along the walls, one short and the other long, on either side of the start box, and to find the reward the rat had to discriminate the distance, i.e., short vs. long wall of the test box. Results showed that control rats were able to make the discrimination, while FF rats were not. The finding suggests that hippocampus plays an important role in processing distance information in general, and distance discrimination in particular.

Animals↗
PubMed1997

[A chronic encapsulated expanding hematoma with cyst formation caused by rupture of arteriovenous malformation: a case report].

A 57-year-old male was admitted to our hospital complaining of a headache with disturbance of consciousness on November 7, 1994. CT scans revealed an intracerebral hematoma of 25ml in volume in the left frontal lobe with adjacent spotty calcification. An arteriovenous malformation (AVM) with a nidus of 2.0 x 2.0cm in size was found to be the cause of the hematoma by cerebral angiography. Since the patient complained of mild right hemiparesis 10 days after the onset, CT scans were taken and a slightly enlarged hematoma with capsule formation was observed. On the 31st day after the onset, the hematoma had liquefied and the surrounding capsule was clearly visible on CT. Since the patient's only symptom was a slight headache, and he displayed no other serious conditions, a palliative operation was planned. The AVM was removed and the capsule was resected 41 days after the onset. The capsule or cyst wall of the liquefied hematoma was composed of three layers: a granulation layer with a neovascular system on the inside, a collagenous layer in the middle, and a reactive brain tissue layer on the outside. The structure of the capsule was the same as the structure of the cyst wall in chronic hematomas that have been reported as cystic AVM or encapsulated expanding hematoma in the literature. We would therefore like to propose that chronic encapsulated expanding hematomas form with time due to intermittent bleeding or exudation form the neovascular system of a cyst wall.

Brain Diseases↗
PubMed1997

cis-Hydroxyproline inhibits proliferation, collagen synthesis, attachment, and migration of cultured bovine retinal pigment epithelial cells.

PURPOSE: Proliferative vitreoretinopathy (PVR) is characterized by the proliferation and migration of retinal pigment epithelial (RPE) and other cells into the vitreous cavity. The PVR membrane formation also is associated with collagen production by RPE. The authors examined the effect of a proline analog, cis-hydroxyproline (CHP), on proliferation, collagen synthesis, attachment, and migration of bovine RPE in vitro. METHODS: The effect of CHP on cell proliferation was determined as a function of dosage and days in culture by counting the cell numbers on days 3, 6, and 9. Collagen synthesis was determined by trichloroacetic acid precipitation of the radiolabeled samples before and after bacterial collagenase digestion. The attachment assay involved type I collagen or fibronectin substrates or both (2.5 micrograms/well). For migration experiments, RPE cells were removed from a defined area of a confluent culture, and migration was quantitated by counting the number of cells migrating into the denuded area over 30 hours. RESULTS: The addition of CHP inhibited RPE proliferation in both a dose- and a time-dependent manner; collagen synthesis, attachment, and migration also were inhibited by CHP in a dose-dependent manner. When the culture plates were coated with collagen, < 100 micrograms/ml of CHP had no effect on cell attachment. Higher doses of CHP resulted in mild inhibition of attachment on collagen-coated plates. Simultaneous addition of L-proline to the cultures resulted in blockade of these inhibitory effects on proliferation, collagen synthesis, attachment, and migration. CONCLUSIONS: The results show that RPE functions critical to the development of PVR are inhibited by CHP, suggesting the possibility that this drug may have potential clinical application.

Animals↗
PubMed1997

[Encephalitis located at bilateral corpus callosum on MRI--a case report].

A case of viral encephalitis is described. A 38 year-old female was admitted because of high fever accompanied by cough and headaches. Two days after admission the patient began to exhibit abnormal behavior. Cerebrospinal fluid examination revealed pleocytosis. T2-weighted MRI revealed a high-intensity area located in the corpus callosum bilaterally that gradually increased in intensity within several days the patient's behavior returned to normal. The high-intensity area on MRI persisted for several months but diminished in intensity. Rubella may have been the etiology of the encephalitis.

Adult↗
PubMed1997

[A surgical case of severe Ebstein's anomaly, pulmonary atresia in the neonate: experience of modified Starnes operation].

We report a surgical case of severe Ebstein's anomaly associated with pulmonary atresia in the neonate. The baby had remarkable cardiomegaly (CTR > or = 90%) soon after birth and presented severe respiratory distress. He underwent modified Starnes operation (closure of tricuspid valve using a perforated patch, enlargement of interatrial communication, modified Blalock shunt, and PDA ligation) at the age of 12 days. He survived the procedure and cardiopulmonary failure was improved. However, he died from arrhythmia on the 3rd postoperative day. We think this procedure is useful regard to improvement of cardiopulmonary failure due to this fatal congenital heart disease.

Cardiac Surgical Procedures↗
PubMed1997

[Effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass in patient undergoing coronary bypass surgery].

We evaluated the effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass (CPB) in patient undergoing coronary bypass surgery comparing with the patients not receiving amrinone. In amrinone treated patients bolus dose of amrinone 1.5 mg.kg-1 was administrated into the reservoir of CPB and followed by continuous infusion at a rate of 5 micrograms.kg-1.min-1. Hemodynamics and blood gas (arterial and mixed venous) measurements were carried out immediately after CPB, 1 hour after CPB and after the chest closure. After the chest closure, cardiac index and oxygen supply in amrinone treated group were significantly higher and systemic vascular resistance was significantly lower than in non-treated group. Left ventricular stroke work index, rate pressure product and oxygen consumption showed no significant difference between the two groups. These data indicate that the amrinone treated patients preserved better oxygen demand-supply relationship after CPB compared with the non-treated patients undergoing coronary bypass surgery.

Amrinone↗
PubMed1997

Free ileocolon transfer after hypopharyngo-laryngo-cervical esophagectomy for speech rehabilitation.

Patients with carcinoma of the hypopharynx or the cervical esophagus usually undergo total laryngectomy with hypopharyngo-esophagectomy and, consequently, lose the power of speech. Therefore, a reconstruction method which would enable speech rehabilitation is desirable following this type of procedure. Free ileocolon transfer consists of colo-esophagostomy, pharyngo-colostomy, ileo-tracheotomy, vascular anastomosis under a microscope, and permanent tracheostomy. In this method, the colon functions as the alimentary tract, while the ileum and ileocecal valve can produce sounds. We evaluated the results in live patients with free ileocolon transfer following hypopharyngo-laryngo-cervical esophagectomy. Although there was no case of direct operative death, one patient died from cancer progression. Four patients are still alive at from 18 to 36 months after operation. Postoperatively, stenosis of the colo-esophaogostomy appeared in two patients, but there was no case of anastomotic breakdown or any other major complication. Speech rehabilitation was good, and there was no misswallowing into the airway. We think that free ileocolon graft is one of the more preferable procedures following hypopharyngo-laryngo-cervical esophagectomy.

Aged↗
PubMed1997

[Trial of a detachable Y-shaped tube with two valves for serial examinations of CT arterial portography and CT hepatic arteriography].

In five patients with hepatocellular carcinoma, CT arterial portography (CTAP) and CT hepatic arteriography (CTHA) were performed serially by using a newly developed detachable Y-shaped tube with two valves that could be attached to a conventional angiographic sheath. Two catheters could be inserted into the conventional angiographic sheath without blood backflow by using the Y-shaped tube. One catheter could be easily and safety placed on the common or proper hepatic artery, and the other on the superior mesenteric artery. This detachable Y-shaped tube with two valves could make it easy to perform serial CTAP and CTHA examinations.

Angiography↗
PubMed1997

[A new mechanically manipulated unit for CT-guided biopsy].

To avoid radiation exposure to the radiologist during biopsy with CT fluoroscopy, we have developed a new system for CT-guided biopsy. The system is composed of three parts, a needle holder, arm and support. The automatic biopsy needle is mechanically remote controlled by flexible shafts with four functions. In the phantom study and the clinical trial, we were able to biopsy nodules under remote control with this equipment, eliminating radiation exposure to the radiologist. Although a few refinements of the system are necessary, it may enable us to perform CT-guided biopsy more safely and easily.

Animals↗
PubMed1997

[Effects of OK-432 intraportal administration on cell-mediated immune responses].

The effects of OK-432 and/or MMC on host immunity were studied in patients with advanced colorectal cancer. OK-432 was administered to the portal vein, and MMC was dispersed into the peritoneal cavity for prevention of liver metastasis. In the MMC group, NK activity was significantly reduced at 7 days postoperatively, while such a reduction was not seen in the OK and OK + MMC groups. The administration of OK-432 decreased the postoperative proportion of suppressor T cells in the lymphocyte subsets more than that of MMC group. Our results strongly suggest that intraoperative administration of BRM to the patients with advanced colorectal cancer can significantly prevent postoperative immunosuppression.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[Circadian chemotherapy in cancer patients].

Continuous infusion of 5-FU at night was performed for four patients: three had liver metastasis (one with gastric cancer and two with rectal cancer) and one had local recurrence of rectal cancer. The chemotherapy schedule was 400 mg/m2/day 5-FU intraarterial or intravenous infusion from 6:00 p.m. to 6:00 a.m. for five days repeated every 3 weeks. There were one complete response, two partial responses and one with no change. It is expected that the chemotherapy of 5-FU at night will result in a high efficacy and lower toxicity.

Adult↗
PubMed1997

[A surgical case for the huge chronic expanding hematoma developed in the thoracic cavity].

We report a case of operation against chronic expanding hematoma developed in the pleural cavity of the patient who were treated as anaplastic anemia. 69-year-old man had been underwent thymectomy because of the thymoma and hemogenic pleural effusion 8 years ago. Then, last year, he was pointed out severe thrombocytopenia and underwent transfusion of thrombocyte. In the same period, chest X-ray examination revealed development of the tumor-like shadow in the left lung field. The abnormal shadow has enlarged, so the patient admitted us. X-ray findings revealed the huge tumor occupied completely the left pleural space. He was also pointed out severe pancytopenia (WBC: 2,600/mm3, RBC: 172 x 10(4)/mm3, thrombocyto: 1.9 x 10(4)/mm#), and the examination of bone marrow revealed anaplastic anemia. Thoracotomy was underwent, and the tumor was resected. Pathological diagnosis of the tumor was huge hematoma. Negative pressure in the pleural space would keep the hemorrhage and make hematoma huge. The hematoma in the pleural space should be resected as soon as the diagnosis is decided.

Aged↗
PubMed1997

[Typical normal cases and normal cases with abnormal image pattern in every myocardial SPECT radiopharmaceutical].

Working group of cardiac nuclear medicine was made as a Japanese part of society of international cardiac nuclear medicine under the cooperation between Japanese society of nuclear medicine and Japanese society of cardiology. We investigated typical normal cases and normal cases with abnormal image pattern in every myocardial SPECT radiopharmaceutical as one of the research activity of working group. From 11 faculties, 16 T1 cases, 14 BMIPP cases, 8 MIBG cases, 8 MIBI cases and 14 tetrofosmin cases were submitted as typical normal cases, and 12 T1 cases, 5 BMIPP cases, 12 MIBG cases, 10 MIBI cases and 5 tetrofosmin cases were submitted as normal cases with abnormal image pattern. We summarized the condition of SPECT data acquisition of each faculties. And we added the discussion from literature about how to discriminate normal cases with abnormal image pattern from abnormal cases. In MIBG, patterns of typical normal cases and normal cases with abnormal image pattern were slightly different from other 4 pharmaceuticals. In other 4 pharmaceuticals, diaphragmatic attenuation, breast attenuation, apical thinning and others were presented as normal cases with abnormal image pattern.

3-Iodobenzylguanidine↗
PubMed1997

Electroporation and bleomycin in glaucoma-filtering surgery.

PURPOSE: To develop a new treatment in glaucoma-filtering surgery using combined treatment with electroporation and the antiproliferative drug bleomycin. METHODS: Pigmented rabbits were treated with both bleomycin (10 micrograms/ml) and localized electric pulses (EP) using a special probe (5 V/cm, 100 msec, 8 pulses) (n = 10; group A). After EP treatment, bleomycin was washed out with 50 ml balanced salt solution, and then a posterior lip sclerectomy was performed on the same area. We also studied rabbits undergoing a posterior lip sclerectomy with bleomycin treatment alone (n = 10; group B), a posterior lip sclerectomy with EP treatment alone (n = 5; group C) and a posterior lip sclerectomy alone using the same operation (n = 5; group D, negative control). The intraocular pressure (IOP) was measured before and 1, 3, 5, 7, 10, 15, and 20 days after surgery. The formation of blebs, the conjunctiva, and the cornea were periodically examined by slit-lamp biomicrography. RESULTS: In every group, the IOP decreased until day 7, and no significant difference was observed among the four groups. In groups B, C, and D (control), the IOP increased gradually from day 10 and thereafter returned to the preoperative level after 15 days. However, in group A, the IOP remained lower than the preoperative level for 20 days; it was also significantly lower than each of the other three groups (P < 0.01). The survival rate of a filtering bleb was significantly higher in group A than in groups B, C, or D, but the survival rate in group B was not higher than groups C or D. No adverse effects were clinically observed in the ocular tissue, such as the cornea and conjunctiva. CONCLUSIONS: The combined treatment with EP and bleomycin was found to decrease IOP more prominently than EP or bleomycin treatment alone in filtering surgery. This treatment thus makes filtering surgery effective by decreasing the dose of the antiproliferative drug and by possibly localizing the drug delivery.

Animals↗
PubMed1997

[A case of traumatic hematoma in the basal ganglia: successful drainage with ultrasound-guided aspiration surgery via burr hole].

A case was reported of massive traumatic hematoma of the basal ganglia which was treated successfully by ultrasound-guided aspiration surgery. A 8-year-old girl was transferred to our hospital 20 minutes after a traffic accident. She was in stupor and had right hemiplegia. A skull x-rays showed right temporal linear fracture and a head CT disclosed left massive putaminal hematoma. Ultrasound-guided aspiration surgery via a burr hole was performed under general anesthesia and 30 ml of hematoma was successfully evacuated. Her symptoms and signs improved gradually and she was discharged on foot 3 weeks after the accident. The clinical feature and mechanism of development of the hematoma in this lesion, and usefulness of ultrasound-guided aspiration surgery were also discussed.

Basal Ganglia↗
PubMed1997

[Intraocular neovascularization].

To investigate the mechanism of intraocular neovascularization, we studied how vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) are expressed in the ocular tissues under hypoxic conditions. Prior to proliferation of vascular endothelial cells resulting in neovascularization, the retinal tissues such as pericytes, retinal glial cells, ganglion cells, and ciliary epithelium react directly to hypoxia expressing VEGF and/or IL-8 and stimulate endothelial cell proliferation in a paracrine manner. We demonstrated that transcription factor activator protein-1 (AP-1) is activated for expression of VEGF messenger ribonuculeic acid (mRNA) and in a similar way nuclear factor kappa B (NF-kappa B) is activated for expression of IL-8 mRNA. However, hypoxia-induced expression of VEGF and/ or IL-8 is only one aspect of the complicated processes in intraocular neovascularization. We hope that further detailed analysis of the mechanism will make it possible to inhibit and treat clinically intraocular neovascularization in the near future.

Adult↗