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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 649 records · Page 36Linked to original sources
PubMed1993

Regeneration of rat urinary bladder epithelium after 12-O-tetradecanoylphorbol-13-acetate (TPA)-treatment: scanning and transmission electron microscopic study.

Rat urinary bladder epithelium consists of basal, intermediate and superficial cell layers. The superficial cells (SP cells) were desquamated after 12-O-tetradecanoylphorbol-13-acetate (TPA)-treatment, and the morphological changes of the regenerating epithelium were investigated by scanning and transmission electron microscopy. Twenty-four hours after TPA-treatment, the epithelium had principally two cell layers and no typical SP cells were observed. During the next 24 hours, the epithelial cell layers became irregular as the epithelial cells with multiform cell projections interdigitated with each other and more than five layers of cell stratification were observed. These cells were bright and had large round nuclei. Their luminal surfaces at this stage were triangular or rectangular. Four days after TPA treatment, epithelial stratification was reduced to approximately three cell layers and some of the luminal cells had recovered the fusiform vesicles. Eight days after TPA treatment, most regions of the epithelium had returned to normal and typical SP cells with many fusiform vesicles had regenerated. These results indicate that the regeneration of bladder epithelium after TPA treatment occurred within about one week.

Animals↗
PubMed1993

[The EEG background activity in children with epilepsy--effects of the removal of anticonvulsants on the EEG].

The development of the EEG background activity is generally impaired in children with epilepsy. Antiepileptic drugs (AEDs) are one of the important factor which influence the EEG background activity. We studied the effect of AEDs on the EEG. Subjects were 46 normal children and 48 children with epilepsy aged 5 to 15, who had not any organic brain damage and showed normal psychomotor development. Forty children with epilepsy (CBZ; 30 cases, VPA; 10 cases) had been on monopharmacy and 8 cases on polypharmacy. All of them have outgrown their epilepsy. The serial EEGs were recorded during withdrawal and after discontinuation of AED in each patient. These records were evaluated using computerized power spectral analysis. CBZ reduction associated with a decrease in delta and theta powers and an increase in alpha-2 power, which were also observed at VPA reduction in concomitant AEDs (VPA+CBZ). No parameter changed by VPA reduction in monopharmacy. The slowing of the EEG background activity was noticed even after discontinuation of CBZ. It required more time after discontinuation of CBZ in younger children than older before the EEG background activity became normal controls. These findings suggested that CBZ had a adverse effect, which was more remarkable in younger children than older children, on the development of EEG background activity and that the effect of CBZ on EEG was different from that of VPA.

Adolescent↗
PubMed1993

[Screening of sleep apnea syndrome using daytime polysomnography--its usefulness and the characteristics of daytime sleep in the patients with sleep apnea syndrome].

Some attempts have been made to screen sleep apnea syndrome (SAS). In this study, we performed daytime polysomnography (DPSG) as a means of screening SAS. 33 patients (28 males and 5 females, a mean age of 50.7 years) who were seen with the complaints of sleep-wake disorders, snoring and breathing disturbance in their nocturnal sleep were subjects for the screening. EEG, EMG, and EOG according to standard polysomnographic technique were recorded from 3:30 (p.m.) for 60 minutes, as additional indicators, oro-nasal airflow and abdominal movement were monitored simultaneously to confirm cessation of breathing. After the screening, we performed conventional polysomnography (PSG) to make a diagnosis of SAS, and compared the diagnosis with the appearance of apnea in the screening. We studied on the characteristics of daytime sleep in SAS and NonSAS by the comparison of EEG variables obtained from DPSG. Sleep apnea was detected in 20 cases with DPSG, 18 cases of these 20 were diagnosed as SAS. However, there were 6 patients who were diagnosed as SAS without the appearance of apnea in the screening. Dominant type of apnea in the screening were corresponded to ones confirmed with PSG, 16 cases showed obstructive type and 4 cases indicated central type. Some statistical differences of EEG variables between SAS and NonSAS were recognized. Number of stage shifts and percentage of stage W to total sleep time were significantly increased in SAS, on the contrary, percentage of stage 2 to total sleep time tended to be lower in SAS.(ABSTRACT TRUNCATED AT 250 WORDS)

Electroencephalography↗
PubMed1993

Polylactic acid-polyethylene glycol block copolymer. A new biodegradable synthetic carrier for bone morphogenetic protein.

A new biodegradable polymer, a polylactic acid-polyethylene glycol (PLA-PEG) block copolymer, proved to be an effective and suitable carrier for bone morphogenetic protein (BMP). Composites of semipurified BMP and PLA-PEG consisting of a PLA segment with a molecular weight (MW) of 650 d and a PEG segment with a MW of 200 d (PLA-PEG 650-200) were implanted under the fasciae of the dorsal muscles of mice. Three weeks after implantation, the PLA-PEG 650-200/BMP composites were completely absorbed and replaced by newly induced bone with hematopoietic marrow. The composites induced twice as much bone as composites of BMP and a 650-d PLA homopolymer. Results indicate that of all the biodegradable synthetic polymers the authors have tested, PLA-PEG 650-200 is the most suitable and effective BMP carrier. Composites of PLA-PEG 650-200/BMP and hydroxyapatite powder (HAP) also induced ectopic bone formation. Because PLA-PEG 650-200/BMP is viscous and semiliquid and PLA-PEG 650-200/BMP/HAP is doughy and plastic, the former can be used as an injectable osteoinductive material and the latter as a plastic mold.

Animals↗
PubMed1993

[Surgical treatment of type A aortic dissection combined with aortic root lesions].

From January 1980 to December 1992, 36 patients with type A aortic dissection were operated on at the St. Marianna University Hospital. Hospital mortality and 10-year survival rate in 26 patients (Group I and II) undergoing replacement of the ascending aorta with or without hemi-arch resection (including one case of aortic wrapping for the closing dissection) were 19.2% and 88.0%, respectively. Among the patients having aortic root destructions due to acute aortic dissection or preexisting annuloaortic ectasia (Group III), 8 patients underwent aortic root reconstruction with a valved conduit and 2 patients supra-coronary aortic resection and graft replacement with concomitant coronary artery bypass grafting with 20.0% of hospital mortality and 55.6% of 10-year cumulative survival rate. Modified Bentall operation using Carrel patch method seems to be preferable to avoid postoperative complications for the case with intimal tear extending to the aortic sinuses, ruptured outer layer of the aortic root or preexisting AAE. If the disrupted coronary artery is concerned, coronary artery bypass grafting is mandatory. In the case of replacement of the ascending aorta for the dissection extending to the aortic sinuses, complete obliteration of the proximal false lumen must be required to avoid uncontrollable bleeding and compromised coronary blood flow.

Adult↗
PubMed1993

[Airborne Japanese red cedar allergens studied by the immunoblotting technique--comparison with pollen counts obtained by Durham sampling and effect of weather].

We collected airborne particles with Burkard's sampling tape in Toyama from March to July. According to the immunoblotting technique (Takahashi et al, 1990), the airborne pollen allergens were reacted with anti-Cry j I polyclonal antibody and were stained as blue spots. The areas of these spots were measured with a color image analyzer (CIA) and a densitometer. There were significant correlations between the airborne Cry j I allergen spots (CIA and densitometer) and the pollen counts obtained with a Durham sampler (r = 0.624, 0.555, p < 0.001). The airborne Cry j I allergens however, tended to maintain a higher level than the pollen counts (Durham) in May. We theorized that this discrepancy is caused by cross reactivity with other pollen or crushed cedar pollen particles have allergenicity. There was a negative correlation between the Cry j I spots and rainfall. The pollen counts had a negative correlation with rainfall, and a positive correlation with average wind speed. These results suggest that this method is useful in evaluating fluctuations in airborne Cry j I allergen.

Allergens↗
PubMed1993

[Evaluation of the Magic Lite SQ specific IgE kit].

The new IgE specific antibody assay kit (Magic Lite SQ) was evaluated by comparing its results with those obtained by the Phadebas RAST and the skin prick tests. Sera from allergic children were used in the tests. The correlation coefficients between the Magic Lite SQ and the Phadebas RAST were as follows: 0.87 for D.p., 0.89 for D.f., 0.87 for HD1, 0.55 for HD2, 0.76 for orchard grass, 0.93 for cat dander, 0.78 for Alternaria, 0.88 for egg white, 0.75 for egg york, 0.81 for milk, 0.75 for say bean, and 0.60 for shrimp. The concordance rate of the two methods was high, except on the case of HD2. The sensitivity and specificity of Magic Lite SQ to the skin prick test was high, except on the case of HD2 and orchard grass. Dilution tests using samples from D.f. positive patients showed a good linearity and excellent quantitativeness. When mite allergen was added to D.f. positive pool serum, mite specific IgE antibody yielded an excellent inhibition curve of up to a maximum of 96%. Since the Magic Lite SQ requires only a small sample of serum and can completed the test in a short time, it is a useful and specific IgE antibody assay kit.

Child↗
PubMed1993

[Evaluation of surgical treatment for spontaneous pneumothorax].

To evaluate the effect of surgical treatment for spontaneous pneumothorax, we examined eighty patients who underwent the surgical treatment. Out of these, thirty five patients (53.0%) were the recurrent episode of the disease, since we vigorously chose surgical treatment for the second attack of the disease. Operative complications were observed in 6 cases (7.1%) including 2 cases of lasting air leakage and 1 case of bleeding, pneumonia, wound infection and atelectasis. Postoperative recurrence was not seen. From a viewpoint of prevention of the postoperative recurrence, the surgical treatment is effective and safe method.

Adolescent↗
PubMed1993

[Use of a rate responsive pacemaker in sick sinus syndrome].

In this study of 10 patients with sick sinus syndrome, we examined the benefits of a single-chamber ventricular pacing system that utilizes a sensor to detect the QT interval and then adjusts the heart rate. Changes in exercise tolerance capacity and cardiac function were evaluated when the pacing mode was changed from rate-variable mode (VVIR) to fixed-rate mode (VVI). Anaerobic threshold (AT), peak VO2 and cardiac output were measured in VVIR, during short-term VVI(VVI-S), which occurred two hours after the pacing mode was changed, and during long-term VVI (VVI-L), which occurred one month after the pacing mode was changed. 8 of 10 cases (80%) had their own beats during exercise. The AT and peak VO2 during VVI-S were not different from those during VVIR. However, AT and peak VO2 during VVI-L were significantly lower than those during VVIR pacing. (Respectively, 11.7 +/- 2.4 vs. 16.4 +/- 3.3, p < 0.01; 21.5 +/- 5.9 vs. 24.6 +/- 6.2, p < 0.01). At AT and peak VO2, there were no differences in cardiac output between VVIR and VVI-S, or between VVIR and VVI-L(NS). Physiologic changes in heart rate and cardiac output after exercise during VVIR were greater than those during VVI pacing. The present study suggests the above-mentioned changes after exercise effect, oxygen consumption in the peripheral circulation, which might lower exercise tolerance capacity in the chronic phase. The rate-variable pacing mode might improve exercise tolerance capacity and may be of benefit for patients with sick sinus syndrome.

Aged↗
PubMed1993

[A successful VA bypass treatment in patient with severe pulmonary hypertension].

Report of a case of a patient with pulmonary hypertension associated with pericardial effusion who was treated by VA bypass during life-threatening right ventricular failure. A 63-year-old man was admitted to our hospital complaining of chest pain and dyspnea. Echocardiography revealed the patient had severe pulmonary hypertension and pericardial effusion. Though there were deep Q waves in ECG, his coronary angiography revealed normal coronary arteries. Pulmonary scintigraphy showed no evidence of pulmonary thromboembolism. As he developed hypotension and anuria, emergency pericardial drainage was carried out without any beneficial effect. Because no effective drugs were found to control his systemic hypotension and pulmonary hypertension, he was treated by VA bypass to save his life. Although his systemic pressure rose to normal level following institution of VA bypass, his pulmonary pressure remained high constantly, around 60-70mmHg. The VA bypass was discontinued on the 6th day because of bleeding tendency. 3 months after VA bypass, though he had not been given any drugs to control pulmonary hypertension, his pulmonary arterial pressure dropped down to within normal range. Though the exact mechanism or etiology of pulmonary hypertension remained unclear, this may be a rare case treated by VA bypass successfully for life-threatening right ventricular failure caused by pulmonary hypertension.

Extracorporeal Membrane Oxygenation↗
PubMed1993

[A new technique for evaluating the respiratory tract--digital subtraction bronchography (DSBG)].

Bronchography is essential for evaluation of morphological changes in the bronchial tree. However, conventional bronchography using Propyliodone (Dionosil) is extremely invasive, especially to those with pulmonary infections. In the present study, we developed a new less invasive method of bronchography with the aid of digital subtraction technique (DSBG), and evaluated its clinical benefits. Bronchography was performed by injecting contrast medium (Iopamidol: Iopamiron 300) via the lumen of the bronchoscope (Olympus Type 20), and image processing of the respiratory tract was performed using digital subtraction technique. From 1991 to 1992, DSBG was performed in 15 cases (8 bronchiectasis, 1 diffuse panbronchiolitis, 1 lung cancer, 1 pulmonary emphysema, and 4 others). DSBG clearly demonstrated the morphological changes of large and segmental bronchial lesions in cases of bronchiectasis and lung cancer, as well as conventional bronchography using Dionosil. In addition, it was possible to image the morphological changes of bronchiolar lesions in diffuse panbronchiolitis and pulmonary emphysema to the same detail as obtained using classical selective alveolo-bronchography (SAB). Since DSBG can provide enhanced images the bronchial tree without being affected by cardiac and respiratory movements, we could obtain detailed information on bronchial and/or bronchiolar lesions. With respect to side effects, Iopamiron was quickly drained and/or absorbed within 2 hours after injection. Pulmonary infection and bronchial bleeding, which are well known primary complications of classical bronchography using Dionosil, were not observed. We conclude that 1) DSBG is useful new technique for examining morphological changes of the respiratory tract, and 2) DSBG is less invasive than conventional bronchography.

Adult↗
PubMed1993

[Partial anomalous pulmonary venous connection to inferior vena cava (incomplete type of scimitar syndrome) in an elderly patient].

A 71-year-old woman presented with recent onset of dyspnea and fatigue on moderate exertion. She had been well during her entire life and had had three pregnancies and deliveries. Cardiomegaly was noted at the age of 30. On physical examination, systolic murmur was detected at the lower left sternal border. The chest X-ray showed cardiomegaly, increased pulmonary vascular markings and elevated right diaphragm. The electrocardiogram showed left ventricular hypertrophy. The echocardiography showed enlargement of right ventricle and atrium, massive tricuspid regurgitation and anomalous venous flow connected to the inferior vena cava from its right-posterior side. Cardiac catheterization demonstrated mild pulmonary hypertension and O2 step-up at the level of the anomalous venous connection to the inferior vena cava. On pulmonary arteriography, left pulmonary venous flow return to the left atrium and atrial septal defect was not found. Veins from the right lung met to form one vessel, went downward, and connected to the inferior vena cava at the level of Th12. L-R shunt was 45% and Qp/Qs was 1.83. Isolated partial anomalous pulmonary venous connection is a rare finding, and it is thought that the natural prognosis is good. The existence of our case, diagnosed at the age of 71, supported this concept.

Age Factors↗
PubMed1993

[Development of the background activity of EEG in children with epilepsy; comparison with normal children].

We investigated the development of the background activity of EEGs in 150 children with epilepsy by means of computerized power spectral analysis, using Fourier transformation by O1 Twenty-seven cases with idiopathic generalized epilepsy (IGE), 30 cases with idiopathic partial epilepsy (IPE), 60 cases with symptomatic partial epilepsy (SPE), 33 cases with cryptogenic partial epilepsy (CPE) and 48 normal children were studied. The records with paroxysmal activity at 01 were excluded in this study. In normal children, total, delta and theta powers showed a significant inverse correlation with age, but alpha-2 and beta-2 powers showed a significant positive correlation with age. In children with epilepsy, there were significant increases of delta and theta powers and a decrease of alpha-2 power compared with normal children. The development of the EEGs was different among the patients with various types of the epileptic syndrome. It was suggested that age, prognosis and anticonvulsants were important factors which influence the EEGs background activity.

Adolescent↗
PubMed1993

[Factors affecting P300 latencies in epileptic children].

Auditory event-related potentials (ERPs) were recorded from 131 epileptic children of 4 to 20 years of age, and the related factors affecting P300 latencies were evaluated using multiple regression analysis. The examined factors were as follows: (1) age at P300 recording and duration of illness, (2) seizure types and epileptic syndromes, (3) anti-epileptic drugs (AEDs), (4) seizure prognosis, (5) organic brain dysfunctions, (6) x-ray CT and (7) EEG background activity and frequency of paroxysms. ERPs were elicited with the oddball paradigm. Five factors of them had significant correlations with P300 latencies. 1) P300 latencies were gradually shortened with age. 2) P300 latencies were prolonged in the patients before and during AED medication compared with those during the period of off-therapy. 3) Symptomatic partial epilepsy showed obviously prolonged P300 latencies. 4) P300 latencies were shortened with increasing alpha 2 power of EEG. 5) P300 latencies became prolonged with the length of illness.

Adolescent↗
PubMed1992

An endothelin B receptor-selective antagonist: IRL 1038, [Cys11-Cys15]-endothelin-1(11-21)

In the inhibition of specific binding of [125I]endothelins (ETs) to membrane from various tissues of rats, guinea pigs, pigs and humans, [Cys11-Cys15]-ET-1(11-21), IRL 1038, has a much higher affinity for ETB receptors (Ki = 6-11 nM) than for ETA receptors (Ki = 0.4-0.7 microM). In contraction assays, with ET-3 as a stimulant, 3 microM IRL 1038 antagonized the ETB receptor-mediated contraction of guinea pig ileal and tracheal smooth muscle without any significant agonistic activity, but did not effect the ETA receptor-mediated contraction of rat aortic smooth muscle. IRL 1038 is therefore, considered to be the first antagonist selective to the ETB receptor.

Amino Acid Sequence↗
PubMed1992

A reversible radioligand specific for the ETB receptor: [125I]Tyr13-Suc-[Glu9,Ala11,15]-endothelin-1(8- 21), [125I]IRL 1620.

Suc-[Glu9,Ala11,15]-endothelin(ET)-1(8-21), IRL 1620, is a linear ET-analog specific for the ET-isopeptide-nonselective ETB receptor. The radio-iodinated analog, [125I]IRL 1620, showed a single class of saturable binding to the ETB receptors in porcine lung membranes with a Kd of 18 pM and a Bmax of 930 fmol/mg protein, which are almost comparable to the values obtained with [125I]ET-3 (6 pM and 900 fmol/mg protein). In competitive binding assays with [125I]IRL 1620, unlabeled ET-1, ET-3, IRL 1620 and [monoiodo-Tyr13]-IRL 1620 showed almost identical displacement curves with Ki of 8 to 16 pM. However, [125I]IRL 1620 was dissociated from the binding sites by addition of an excess amount (100 nM) of any of these unlabeled peptides, each with the same t1/2 of 100 min. This was in marked contrast to [125I]ET-3 which was hardly dissociated from the binding sites.

Animals↗