Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 631 records · Page 35Linked to original sources

PubMed1993

24-hour ambulatory blood pressure variability in obstructive sleep apnea syndrome.

The 24-h ambulatory blood pressure (24h-ABP) was examined in 21 men, aged 38 to 65 years (mean 50.6), with obstructive sleep apnea syndrome (OSAS) and in 123 normal male control subjects, aged 40 to 60 years (mean 48.1) who did not have OSAS, obesity, autonomic nervous system abnormality, cardiac disease, or respiratory disease (group C), to assess the role of apneas in the circadian variation of blood pressure (BP). The 24h-ABP patterns in OSAS patients were classified into three types as follow: normotensive OSAS patients with normal BP throughout the 24-h period with nocturnal BP fall (type 1); hypertensive OSAS patients with progressive BP elevation from onset of sleep to early morning (type 2); and hypertensive OSAS patients with elevated BP (systolic BP > or = 140 mm Hg or diastolic BP > or = 90 mm Hg) at any time during a 24-h period (type 3). It was concluded that the circadian BP variation in type 1 was almost identical to the level and pattern of group C; the circadian variations in types 2 and 3 were significantly different from that of group C; and the patients with types 2 and 3 BP patterns had more severe OSAS than type 1 patients. The severity of OSAS was an important factor in nocturnal elevation of BP, hence affecting the circadian variation of BP. Noninvasive 24h-ABP monitoring is a useful procedure for understanding the clinical features of OSAS patients with or without hypertension.

Adult↗

PubMed1993

Mid-term results of bilateral internal thoracic artery grafting.

Forty patients underwent coronary revascularization using bilateral internal thoracic artery (ITA) grafts between 1988 and 1992. A total of 111 coronary grafts were performed, or an average of 2.8 grafts per patient. Each patient received bilateral ITA grafts, and in 20 patients an additional 29 grafts were constructed with 18 autologous veins and 11 gastroepiploic arteries. The right ITA was grafted as a free graft in 20 patients. The ITA graft patency rate was 96 per cent (67/70) at the time of hospital discharge. The operative morbidity included 3 reoperations for bleeding, 1 perioperative myocardial infarction, 1 renal failure, 2 postcardiotomy shock, and 1 colon perforation. Two hospital deaths occurred; one due to colon perforation and the other due to postcardiotomy cardiogenic shock. One patient died of cerebral infarction 6 month after the operation. Thirty-four patients were in New York Heart Association functional class I, 2 were in class II and 1 was in class III. Cardiac function evaluated by echocardiography and scintigraphy showed significant improvement postoperatively. These data suggest that the use of bilateral ITA grafts is associated with an acceptable mortality and increases the versatility of arterial grafting.

Aged↗

PubMed1993

Penetrating injury of the transverse sinus by a nail-gun--case report.

A 46-year-old male presented with a penetrating injury of the transverse sinus caused by a nail-gun. Open craniotomy reflected a doughnut-shaped bone flap and the 45 mm long nail, which was fortunately only touching the edge of the sinus, successfully removed. A wide surgical exposure and careful manipulation of the embedded nail are important to avoid inadvertent injury to the venous sinus and the surrounding brain tissues during the surgical procedure.

Accidents, Occupational↗

PubMed1993

Unusual meningeal tuberculoma--case report.

A 60-year-old male presented with bilateral papilledema. Neuroimaging showed a densely enhanced flat tumor within the interhemispheric region in the frontal and parietal lobes with sulcal obliteration and enhancement. There was no history of tuberculous infection. Histological examination of the excised tissue from the flat tumor within the interhemispheric region was consistent with tuberculoma. Multiple antituberculous agent therapy resolved the papilledema and reduced the tumor.

Diagnosis, Differential↗

PubMed1993

Ultracytochemical study of ouabain-sensitive K(+)-dependent p-nitro-phenylphosphatase activity in stria vascularis of reserpinized guinea pigs.

In order to clarify the effect of reserpine on the Na(+)-K+ active transport in the stria vascularis we investigated the localization of ouabain-sensitive K(+)-dependent p-nitro-phenylphosphatase (K-NPPase) activity in the stria vascularis of reserpinized guinea pigs using the cerium-based method. The K-NPPase activity in marginal cells differed from cell to cell, and was almost completely absent in some cells. These results are consistent with the previous results and suggest that Na(+)-K+ active transport in the stria vascularis may be inhibited by reserpine administration.

4-Nitrophenylphosphatase↗

PubMed1993

Differential sensitivity to interleukins of CD5+ and CD5- anti-DNA antibody-producing B cells in murine lupus.

We studied the effects of interleukins (IL) on in vitro IgM and IgG anti-DNA antibody production by splenic B cells from autoimmune disease-prone NZBxNZW (NZB/W) F1 mice. It was found that different interleukins regulate phenotypically distinct B cells producing separate isotype of anti-DNA antibodies. IL-2 slightly but significantly inhibited the production of IgM anti-DNA antibodies. IL-4 and IL-6 significantly enhanced the antibody production, but the effects were not so marked and inconsistent, particularly with respect to IL-6. By contrast, the effects of IL-5 were remarkable, particularly on splenic B cells from young mice. As for IgG anti-DNA antibodies, IL-6, but not other interleukins, markedly up-regulated the antibody production by splenic B cells from mice over 6 months of age, in a dose dependent fashion. Thus, the ability of B cells to produce IgG anti-DNA antibodies appears to be dependent on the surface expression of IL-6 receptor (IL-6R) at the ages when the mice begin to develop the disease. Studies of the surface phenotypes showed that while the IL-5-sensitive major IgM anti-DNA producers were CD5+Lp-3(CD43)-sIgM+, the IL-6-sensitive major IgG anti-DNA producers were CD5-Lp-3+sIgM-. However, significant amounts of IgG antibodies were also produced, in the presence of IL-6, by CD5+Lp-3+sIgM+, but not by CD5-Lp-3+sIgM+ B cells from 6-month-old mice. We suggest that surface phenotypes of anti-DNA antibody producers change from CD5+Lp-3-sIgM+IL-5R+, CD5+Lp-3+sIgM+IL-6R+ and subsequently to CD5-Lp-3+sIgM-(sIgG+)IL-6R+ in NZB/W F1 mice with aging.

Animals↗

PubMed1993

A selective agonist of endothelin type B receptor, IRL 1620, stimulates cyclic GMP increase via nitric oxide formation in rat aorta.

The signal transduction pathways of endothelin (ET)-induced vasorelaxation in rat aorta were investigated. An agonist for ETB receptors, IRL 1620, induced transient increases in cytosolic Ca++ (peak at about 10 sec) and cyclic GMP (peak at about 20 sec) accompanied by transient vasorelaxation (peak at about 60 sec) in aortic strips precontracted with 100 nM norepinephrine. The cyclic GMP content was increased 3- to 6-fold from the basal level (1.6 +/- 0.2 fmol/micrograms of protein) with 1 nM to 1 microM IRL 1620. The cyclic GMP elevation was endothelium-dependent, abolished in the presence of 100 microM NG-monomethyl-L-arginine, an inhibitor of nitric oxide synthase, and recovered after the further addition of 1 mM L-arginine. An ETB receptor antagonist, IRL 1038 (3 microM), inhibited completely the cyclic GMP increase induced by 100 nM IRL 1620 (8.1 +/- 0.6 fmol/micrograms of protein) without affecting the basal level. On the other hand, an ETA receptor antagonist, 3 microM BQ-123, enhanced significantly both the basal level (3.7 +/- 0.6 fmol/micrograms of protein) and the IRL IRL 1620-induced production (12.2 +/- 0.8 fmol/micrograms of protein) of cyclic GMP. Specific binding sites for [125I]IRL 1620 were detected in rat aortic membranes with a dissociation constant of 37.0 pM and maximal binding capacity of 36.6 fmol/mg of protein, which disappeared after removing the endothelium. Unlabeled ET-1, ET-3, IRL 1620 and IRL 1038, but not BQ-123, displaced the binding of [125I]IRL 1620 with inhibitory constants of 38.5 pM, 36.6 pM, 97.8 pM and 8.9 nM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗

PubMed1993

Effects of ethanol on the motility of papillary sphincter and exocrine pancreas in the monkey.

The effects of acute and chronic ethanol administration on the motility of the papillary sphincter, pancreatic duct pressures, and exocrine pancreas were studied. Acute administration (n = 5) significantly reduced the peak pressure of the papillary sphincter from 84.2 +/- 19.6 to 15.8 +/- 3.0 mm Hg (p < 0.05) and increased the frequency from 0.041 +/- 0.002 to 0.067 +/- 0.005/s (p < 0.01). Chronic administration (n = 5) significantly increased pancreatic duct pressure and frequency of the papillary sphincter from 8.6 +/- 2.9 to 22.1 +/- 2.9 mm Hg (p < 0.01) and from 0.039 +/- 0.002 to 0.071 +/- 0.004/s (p < 0.01), respectively. However, it reduced the peak pressure of the papillary sphincter from 84.8 +/- 15.1 to 21.1 +/- 2.8 mm Hg (p < 0.05). Electron microscopy showed dilation and a concentric arrangement of the rough endoplasmic reticulum in the acinar cells. The exocrine function test showed an increased concentration and output of bicarbonate, protein, and amylase. These findings suggest that chronic alcohol intake may cause papillary dysfunction and pancreatic exocrine hypersecretion, which could play a role in increasing pancreatic duct pressure.

Amylases↗

PubMed1993

Effects of gamma-interferon on collagen and histamine content in bleomycin-induced lung fibrosis in rats.

Recombinant rat gamma-interferon was found to inhibit collagen accumulation induced by the intratracheal administration of bleomycin in rat lungs. gamma-Interferon also elicited a reduction in histamine content in the lungs of the bleomycin-treated rats; however, this agent did not cause any obvious changes in inflammatory cell infiltration into the lung. These results suggest that gamma-interferon inhibits the development of pulmonary fibrosis by suppressing collagen synthesis and could thus be used as a therapeutic agent for preventing this condition.

Animals↗

PubMed1993

Dihydropyridine-sensitive calcium current mediates neurotransmitter release from bipolar cells of the goldfish retina.

The release of neurotransmitter is evoked by activation of the Ca current (ICa) at presynaptic terminals. Though multiple types of ICa have been reported in various cells, little is known about the properties of presynaptic ICa in the vertebrate CNS. The aim of this article is to identify the type of ICa involved in the release of neurotransmitter from retinal bipolar cells. Bipolar cells with a large axon terminal were isolated enzymatically from the goldfish retina, and studied by the following techniques: (1) recordings of ICa in the whole-cell recording configuration, (2) visualization of intracellular free Ca2+ concentration ([Ca2+]i) with the Fura-2 imaging system, and (3) real-time electrophysiological bioassay of released excitatory amino acid transmitter by a voltage-clamped horizontal cell isolated from the catfish retina. The only ICa found in bipolar cells was the high-voltage-activated, dihydropyridine-sensitive type. This result supports the recent study by Heidelberger and Matthews (1992). When ICa was activated by a short depolarizing pulse, a rapid increase of [Ca2+]i was restricted to the axon terminal. A much slower and smaller increase of [Ca2+]i was sometimes observed at the cell body, probably due to the diffusion of intracellular free Ca2+ from the axon terminal. The increase of [Ca2+]i was completely suppressed by nicardipine, suggesting that Ca2+ entered through dihydropyridine-sensitive Ca channels located mainly at the axon terminal. Activating ICa of the bipolar cell evoked a transmitter-induced current in the excitatory amino acid probe (i.e., the catfish horizontal cell). Both currents were suppressed concomitantly by nifedipine but not by omega-conotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1993

[Sleep-disordered breathing in Japan: an overview].

Questionnaires were answered by 3,243 presumably healthy subjects who underwent regular medical checkups in four cities. The prevalences of risk factors for sleep-disordered breathing (SDB) were as follows; habitual snoring was reported by 13-16%, excessive daytime sleepiness by 8-9%, insomnia by 7-13% and systemic hypertension by 5-13%. Polysomnographic studies performed on some possible SDB cases who were selected by the presence of risk factors estimated that the average prevalence of SDB in the present population would be in the range of 1.14-1.94%. Secondly, questionnaires were sent to the main hospitals and institutes involved in the management of patients with SDB, asking about diagnostic criteria, number of SDB patients, management, effectiveness of treatment, etc. The total number of patients registered at those hospitals was 2,751 in 1991. Of the 132 patients who were followed for more than six months, the efficacies of body weight loss, medications, nasal CPAP and UPPP were compared. Based on the analyses of the 279 patients examined some tentative vriteria for diagnosis and for treatment are proposed.

Female↗

PubMed1993

[A clinical evaluation of S-1108 in the treatment of pediatric infections].

1. S-1108 granules were administered to 22 children with bacterial infections (8 cases of bronchitis, 1 case of pneumonia, 3 cases of scarlet fever, 2 cases each of tonsillitis, pharyngitis, pertussis, purulent lymphadenitis and impetigo). 2. Clinical efficacies were excellent in 12 patients and good in 7, fair in 1, poor in 1 and unevaluable in 1 with an efficacy rate of 90.5%. 3. Neither side effects nor abnormal laboratory test values were observed. 4. There was no rejection of the drug during the therapy. From the above results, we consider S-1108 in granular form to be a useful and safe drug in the treatment of various bacterial infection in pediatric patients.

Administration, Oral↗

PubMed1993

[Severe carotid artery stenosis in the neck is frequently associated with coronary heart disease].

We have reviewed 15 cases of carotid artery stenosis in the neck, consisting of 11 patients with cerebral ischemia and 4 asymptomatic patients, in relation to associated coronary heart disease. The 15 patients had systemic complications, including hypertension in 87%, diabetes mellitus in 40% and hyperlipidemia in 57%. Systemic vascular complications other than coronary heart disease were present in 27% of the patients. Three of the 15 patients had a history of ischemic heart disease and had been treated by cardiologists. One patient developed angina pectoris on the second day of a cerebral ischemic attack. Coronary angiography (CAG) and simultaneous cerebral angiography following carotid endartectomy (CEA) were performed 4 of the remaining 12 patients, who had symptoms or history of ischemic heart attacks. Three of these four patients had stenotic lesions in their coronary arteries. Another one patient among the remaining 8 developed angina pectoris one year after undergoing CEA. This patient had 3-vessel coronary artery disease. These findings suggest that a strong correlation between stenotic lesions of the carotid arteries in the neck and coronary heart disease, with or without episodes of ischemic heart disease. CAG should be strongly recommended in such patients to assess the severity of complicating ischemic heart disease and to improve the prognosis following CEA.

Adult↗

PubMed1993

[Aneurysmal bone cyst of the sixth cervical spine: case report].

A 19-year-old girl was admitted with a history of difficulty in moving her neck for several years and a sudden onset of neck pain three months before. Plain radiographs of the cervical spine revealed destruction of the left half of the 6th cervical body with an expansive soap-bubble appearance. Neurological examination on admission was within normal limits. The angiography and bone scintigraphy revealed no abnormality. MRI of T1-weighted image showed a cystic lesion with various signal intensities. T2-weighted image demonstrated a hyperintense balloon-like lesion in the vertebral body and left lamina. At surgery, a cystic tumor was fully extirpated by the posterior approach and the bony defect was packed with apatite granules. She was discharged without any neurological deficits. This disease should be considered as one of the etiologies when a patient with difficulty in neck movement is encountered in young generation.

Adult↗

PubMed1993

[High dose nicardipine therapy for delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage].

The effect of high dose nicardipine on delayed cerebral vasospasm was studied in 33 patients with aneurysmal subarachnoid hemorrhage (SAH). Intravenous infusion of nicardipine started before or immediately after early operation. The dosage was from 4 to 10 mg/h with an average of 7.4 mg/h. The duration was from 2 to 17 days with an average of 12.3 days. Symptomatic vasospasm was observed in only one (3%) out of 33 patients. The remaining 32 patients (97%) showed neither ischemic symptoms nor low-density areas on computed tomography. Severe angiographical vasospasm was diagnosed in 3 patients, who entered hospital on day 3 to 5 after initial attacks. They were operated upon on day 4 to 6 under the administration of nicardipine before or immediately after the operation. No patients showed symptomatic vasospasm and angiographical vasospasm was improved markedly. The present study demonstrated that high dose nicardipine appeared to prevent both brain ischemia and angiographical vasospasm after aneurysmal SAH.

Adult↗

PubMed1993

[The relationship between P300 latencies, and WISC-R and Wechsler memory scale results in epileptic children].

Auditory event-related potentials (ERPs) were recorded in 35 epileptic children of 9 to 13 years of age, and compared with conventional test batteries of cognitive functions. ERPs were elicited with the auditory oddball paradigm. Corrected P300 latencies showed an inverse correlation with the total score (IQ) of WISC-R and that of the Wechsler memory scale (WMS). A strong inverse correlation was also observed with specific items of these test batteries, as follows; "comprehension", "picture completion" and "coding" in WISC-R, and "associated learning", "digit span", "visual reproduction", "mental control", "orientation" and "information" in WMS. These findings suggested that the prolongation of P300 latencies in epileptic children are related with the impairment of cognitive functions. The P300 latency is correlated with a characteristic kind of cognitive function; "simple recognition", "short term memory" and "easy judgement".

Adolescent↗

PubMed1993

[Combination therapy of ESWL and PNL for the staghorn calculi].

We have been engaged in the treatment of urinary tract calculi using extracorporeal shockwave lithotripsy (ESWL) and endourology techniques for more than 8 years. In the treatment of thin staghorn calculi, ESWL monotherapy is the first choice. On the other hand, combination of percutaneous nephrolithotomy (PNL) and ESWL is important for the treatment of thick staghorn calculi in order to avoid the stone street and side effects of shock waves. When the stone is made of hard components such as calcium oxalate monohydrate and cystine, combination of both methods is also useful. In the case of complicated staghorn calculi with isolated branches, open surgery such as nephrolithotomy or partial nephrectomy might be the choice.

Combined Modality Therapy↗

PubMed1993

[Histological study in renal grafts--macrophages population in renal grafts].

We studied about the histological findings of the kidneys including of the infiltrated macrophages in one hour post-transplantation kidney biopsies (one hour biopsies) and re-biopsies on 11 patients. They were transplanted at 4-28 (ave. 15.1 +/- 3.8) years of age. The periods from transplantation to this study were 1.0-7.3 (ave. 3.3 +/- 1.9) years. 6 patients had acute rejections, and their renal function became normal after treatments. At this study, all grafts survived, and the patients had no abnormal findings except two (one had proteinuria, another had proteinuria and mild elevation of serum creatinine level). But histologically, five patients had chronic rejections among the 8 patients who had re-biopsies more than one year after transplantation. And we experienced 6 patients whose kidney had mesangial IgA deposits in one hour biopsies and 3 patients who had de novo type glomerulonephritis in re-biopsies (IgA neuropathy in 2 patients, membranous nephropathy in one). In one hour biopsies, the populations of macrophages in the interstitium were 4.18 +/- 2.84/mm2 in the patients who would have acute rejections (6 patients), 1.38 +/- 1.13/mm2 in the cases who would not have. It was suspected that the increase of the infiltrated macrophages in the interstitium in one hour biopsies could predict acute rejections. In re-biopsies, many macrophages infiltrated in the interstitium (8.34 +/- 4.86/mm2), particularly on patients who had chronic rejections.

Adolescent↗