Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 775 records · Page 43Linked to original sources

PubMed1990

In vivo localization of antitumor lymphocytes separated with Dolichos biflorus lectin.

We examined the in vivo localization of Con A sup-cultured murine splenocytes separated with Dolichos biflorus agglutin (DBA) to elucidate the mechanism underlying the high antitumor efficacy of cells which are not agglutinable with DBA (DBA- cells). First, 51Cr-labeled DBA-separated cells were injected intravenously (i.v.) into mice and then the tissues were collected for gamma counting. DBA- cells showed significant localization in the spleen, compared with DBA+ cells. This was further confirmed by injecting Thy1.2-positive DBA- cells into Thy1.1 congenic mice. Furthermore, after [3H]TdR-labeled DBA-separated cells had been injected i.v., the spleens of the recipients were fixed, sectioned and processed for autoradiography to determine in which region of the spleen the labeled cells had accumulated. We found that DBA- cells were especially concentrated in the white pulp of the spleen, where lymphocytes are localized before being recirculated. These results suggest that DBA- cells exert strong antitumor activity in vivo partly due to their localization in the spleen and partly to the high incidence of active recirculation.

Animals↗

PubMed1990

Anti-tumour efficacy of mouse spleen cells separated with Dolichos biflorus lectin (DBA) in experimental pulmonary metastasis of B16 melanoma cells.

Anti-tumour effector cells were generated through 4 days culture of normal C57BL/6 splenocytes in a medium containing concanavalin A supernatant and then fractionated with Dolichos biflorus lectin (DBA) into DBA+ (agglutinable with DBA) and DBA- (non-agglutinable with DBA) cells. The DBA- cells, infused intravenously into mice together with B16 melanoma cells, or adoptively transferred into mice 3 days after the injection of B16 cells, caused a marked decrease in the number of lung nodules, while the DBA+ cells exerted no effect. On the other hand, the DBA+ cells exhibited higher cytolytic activity in vitro than the DBA- cells in short-term 51Cr-release assays. Then, we analysed the mechanism of the strong anti-tumour activity of DBA- cells in vivo. We found that DBA- cells showed higher response to recombinant interleukin-2 (rIL-2) than DBA+ cells and proliferated very well with a small amount of IL-2. In addition, DBA- cells adhered more strongly to lung endothelial cells than DBA+ cells in response to rIL-1 or rTNF. Furthermore, DBA- cells produced larger amounts of macrophage activating factor (MAF) including IFN-gamma when cultured with B16 melanoma. Taken together, our results show that DBA- cells are effective in reducing experimental pulmonary metastases not only by the direct lytic activity but also by the indirect killing activity through the activated macrophage.

Animals↗

PubMed1990

Bathoiodopsin, a primary intermediate of iodopsin at physiological temperature.

Measurement of the primary photochemical reaction of iodopsin, a chicken red-sensitive cone visual pigment, was carried out at room temperature by using picosecond (ps) laser photolysis. Excitation of iodopsin with a ps green pulse (pulse width, 21 ps) caused the instantaneous formation of a bathochromic product, which was stable on a ps time scale. This product may correspond to "bathoiodopsin," which was detected by low-temperature spectrophotometry. Although bathoiodopsin produced at the temperature of liquid nitrogen or helium reverted to the original pigment (iodopsin) on warming (above -170 degrees C), the bathoiodopsin produced at physiological temperature decayed to all-trans-retinal and R-photopsin (the protein moiety of iodopsin) presumably through several intermediates. The absorption maximum of bathoiodopsin at room temperature was at 625 nm, a wave-length slightly shorter than that measured at low temperature (lambda max, 640 nm). The extinction coefficient of bathoiodopsin at room temperature was lower than that at low temperature and close to that of the original iodopsin at room temperature.

Animals↗

PubMed1990

Fibrin-dependent activation of plasminogen by a proteolytic digest of streptokinase.

Among four enzymatic digests of streptokinase (SK), the smallest peptide with plasminogenolytic activity was in a tryptic digest; it had a molecular weight of 29,000. A complex of this peptide, SK29, and human plasminogen hydrolysed human fibrin, but a complex of native streptokinase and human plasminogen hydrolysed both human and bovine fibrin. The complex with SK29 caused amidolysis of the synthetic substrate S-2251 in the presence of human fibrin, but was inactive in the presence of human fibrinogen, bovine fibrinogen or bovine fibrin. Analysis of the amino terminal sequence of SK29 indicated that cleavage by trypsin was on the carboxyl side of lysine, the 59th amino acid of streptokinase. These results suggest that the conformational changes caused by human fibrin formation resulted in the generation of an active site of human plasminogen by SK29.

Amino Acid Sequence↗

PubMed1990

A rat femoral artery model for vasospasm.

A new animal model for vasospasm using rat femoral artery has been developed. Whole blood, washed erythrocytes, or leukocytes in platelet-rich plasma were selectively applied to the adventitial surface of the femoral artery for 7 days in 15 rats, after which the vessels were perfusion-fixed and examined by light and transmission electron microscopy and immunohistochemistry. As compared with matched control arteries, there was a prominent reduction in luminal cross-sectional area after 7 days in vessels exposed to whole blood or washed erythrocytes, but not in those exposed to leukocytes in platelet-rich plasma. In arteries with luminal narrowing, light and transmission electron microscopy demonstrated marked morphological changes throughout the vessel wall similar to those seen in cerebral vasospasm after subarachnoid hemorrhage. Immunohistochemistry disclosed a prominent loss of immunoreactive actin in smooth muscle cells of arteries exposed to whole blood or erythrocytes. To assess the time course of arterial narrowing in this model, whole blood was selectively applied to the adventitial surface of femoral arteries in 23 rats for periods from 2 to 20 days. As compared with control arteries, arterial narrowing was variably present at 2 days, progressively increased by 5 days, was maximal at 7 to 10 days, and returned to near control levels by 20 days. The presence and severity of ultrastructural changes in vessel wall corresponded to the degree of arterial narrowing over time. These results suggest that chronic narrowing in rat femoral artery exposed to periadventitial blood is analogous to that observed in cerebral arterial vasospasm after subarachnoid hemorrhage. This new model represents a simple and reliable means to investigate pathogenic mechanisms and potential therapies for vasospasm.

Animals↗

PubMed1990

Organic acid and acylcarnitine profiles of glutaric aciduria type I.

Urinary organic acid and acylcarnitine profiles from a 2-month-old boy were studied by gas chromatography-mass spectrometry and fast atom bombardment mass spectrometry. The patient excreted large amounts of glutaric acid and significant amounts of 3-hydroxyglutaric acid, glutaconic acid and glutarylcarnitine, and his serum glutaric acid level was markedly elevated. Thus he was chemically diagnosed as having glutaric aciduria type I (GAI). In addition to the above metabolites previously described in GAI, significantly increased excretion of 2-ketoglutaric acid, succinic acid, adipic acid, adipylcarnitine, suberic acid and azelaic acid was found. 2-Ketoadipic acid methylsuccinic acid and ethylmalonic acid were also detectable, suberylcarnitine was not increased, and dehydroadipylcarnitine was decreased in his urine. These results suggest that excess glutaryl-CoA causes the competitive inhibition of the dehydrogenation of adipyl-CoA to dehydroadipyl-CoA and results in an increase of adipic acid and adipylcarnitine and a decrease of dehydroadipylcarnitine. It is also suggested that oxidative decarboxylation of 2-ketoglutaric acid to succinyl-CoA is inhibited by high levels of glutaryl-CoA, and that the dehydrogenation of succinic acid to fumaric acid is inhibited owing to the increased glutaric acid derived from excess glutaryl-CoA. These results indicate that gas chromatography-mass spectrometry is the most appropriate and accurate method for the differential chemical diagnosis of GAI and glutaric aciduria type II.

Acylation↗

PubMed1990

Asymptomatic low molecular weight proteinuria in children.

We reviewed the clinical features in 7 boys with asymptomatic low molecular weight proteinuria. The disease had first been reported by us in 1980. The distinctive features common to all patients were male dominance, asymptomatic proteinuria with a large amount of low molecular weight proteins, normal development and growth, normal renal function tests in childhood, and minimal histological changes in renal biopsy specimens. In 1990, 35 cases have been reported in Japan. Thus, asymptomatic low molecular weight proteinuria is not a rare disease and is one of the causes of isolated proteinuria. Furthermore, this condition is recognized as a new entity.

Adolescent↗

PubMed1990

[The causative agent from a patient with spotted fever group rickettsiosis in Japan on Awaji Island, Hyogo].

Misaka strain was isolated as the causative agent from a patient with spotted fever group rickettsiosis in Japan by using nude mice on Awaji Island, Hyogo in September 1988. The nude mice infected with the isolate showed weakness and splenomegaly and died in two or three weeks after the infection. The cyclophosphamide-treated mice infected with the isolate died between four and seven days after the infection. The infected normal mice recovered and acquired immunity. The infected adult male guinea pigs were feverish and showed swelling and redness of the scrotum between two and eight days after the infection, and recovered. The Misaka strain was propagated well in Vero cells in tissue culture. The rickettsial particles were seen as diplobacillary and diplococcal forms growing predominantly in the cytoplasm and occasionally in the nucleus of infected cells. The serological characteristics of the Misaka strain were analyzed by the cross-immunofluorescent antibody method. The Misaka strain, the Katayama strain first isolated in Tokushima in 1987, and the representative strains of spotted fever group rickettsiae in the world; R. rickettsii Smith, R. sibirica 246, R. conorii Moroccan, R. akari MK (Kaplan), R. australis Phillips, R. montana Tick and Thai TT-118 strains were used as antigens. And immune mouse serum samples against the Misaka, Katayama, 246, Phillips and TT-118 strains were used as antisera. The result revealed that these strains showed cross-reaction and share a common antigen of spotted fever group rickettsiae. Furthermore, it became obvious that the Misaka strain and the Katayama strain have the same serotype-specific antigen different from the strains of other spotted fever group rickettsiae using Anti-Katayama monoclonal antibodies.

Adult↗

PubMed1990

[Spotted fever group rickettsiosis on Awaji Island, Japan].

Three cases of spotted fever group rickettsiosis occurring on Awaji Island, Hyogo Prefecture, the first reported in the Kinki District, are described. The illness appeared from August to September in 1988. High-grade fever and papular erythema were observed in all cases. Eschar, lymphadenopathy and hepatomegaly were observed in two-thirds of the cases, respectively. The antibody titers for Proteus OX-2 by the Weil-Felix reaction were elevated, and immunofluorescence test with R. rickettsii of the spotted fever group demonstrated a significant rise in specific antibody titer. Tetracycline was effective in all cases. Every patient was thought to have been infected with rickettsiae in the Yuzuruha mountain range in the southern part of Awaji Island. On the other hand, tsutsugamushi disease occurs in autumn and winter in the northern part of Awaji Island. It would be of considerable interest from an epidemiological viewpoint to study the vector of these spotted fever group rickettsiae.

Adult↗

PubMed1990

[A successfully treated case of infective endocarditis due to Candida tropicalis].

A 34-year-old man, a heavy drinker, was admitted with a high fever and hematuria two months previously. Surgery was performed for acute sever pancreatitis and postoperatively antibiotics were administered with intravenous hyperalimentation. After discharge he was readmitted and infective endocarditis was strongly suspected because of high fever, hematuria, Osler's nodes, Janeway's lesions, splinter hemorrhages and mitral regurgitation. Penicillin G in combination with Gentamycine therapy was started on the first hospital day. On the second hospital day, blood culture revealed Candida tropicalis so Miconazole therapy was commenced. On the forth hospital day, he underwent surgery for replacement of a mitral prosthesis with a prosthetic valve because he had embolus in the radial artery. Despite intensive antifungal therapy, he showed no improvement in clinical symptoms. Then we changed the antifungal drug from Miconazole to Amphotericin B and 5-fluorocytosine. On the 109th hospital day, his clinical symptoms improved. Antifungal therapy was halted and at present 10 months later, he is healthy.

Adult↗

PubMed1990

Causative agent of spotted fever group rickettsiosis in Japan.

Since 1984, it has been known that spotted fever group rickettsiosis exists in Japan. We isolated three strains of the causative rickettsiae, designated Katayama, Misaka, and Abe, from patients with the disease and studied the characteristics of the isolates. Nude mice and cyclophosphamide-treated mice died after infection with the isolates. However, infected normal mice recovered and acquired immunity. Infected adult male guinea pigs had fever, a scrotal reaction, and seroconversion. The isolates propagated well in tissue-cultured Vero cells. Analysis by the cross-immunofluorescence antibody method showed that these isolates were closely related serologically. To reveal their immunological properties in detail, we produced 21 anti-Katayama monoclonal antibodies. Seven of these antibodies reacted with all representative strains of spotted fever group rickettsiae used in this study, and five others reacted only with the homologous strain, revealing that the Katayama strain has a strain-specific antigen(s) different from those of other spotted fever group rickettsiae. Moreover, these strain-specific antibodies also reacted with the Misaka and Abe strains. These results demonstrate that the causative agent of spotted fever group rickettsiosis in Japan is a new serotype of spotted fever group rickettsiae.

Animals↗

PubMed1990

Successful use of vancomycin hydrochloride in the treatment of lactulose resistant chronic hepatic encephalopathy.

Vancomycin hydrochloride (2 g daily) was administered to 12 patients with cirrhosis and lactulose resistant portal systemic encephalopathy in a double blind crossover trial. All 12 patients showed a remarkable clinical improvement after vancomycin treatment. The mean (SE) electroencephalographic (EEG) frequency changed from 6.3 (0.2) to 8.5 (0.2) cps (p less than 0.001) and the mean arterial ammonia concentration from 152 (4) micrograms/ml to 97 (8) micrograms/ml (p less than 0.001). Their clinical condition deteriorated when treatment was switched to lactulose, returning to the previous slower EEG frequency and high arterial ammonia concentrations. Vancomycin seems to be effective in chronic portal systemic encephalopathy in patients who are not helped by lactulose alone.

Ammonia↗

PubMed1990

Bifemelane induces translocation of protein kinase C in the CA3, but not the CA1, region of guinea-pig hippocampus.

We made use of the [3H]phorbol 12,13-dibutyrate binding assay to investigate the effects of bifemelane on the subcellular distribution of protein kinase C in the CA3 and CA1 regions of guinea-pig hippocampal slices. Bifemelane, a drug that augments the long-term potentiation in the CA3 region, significantly induced the translocation of [3H]phorbol 12,13-dibutyrate binding activity from the cytosol to the membrane in a dose-dependent manner (10(-8) to 10(-6) M) and with no effects on total binding activity in the CA3 region. Bifemelane, at a concentration of 10(-6) M, was without effect on the subcellular distribution of [3H]phorbol 12,13-dibutyrate binding activity in the CA1 region. These observations suggest that bifemelane acts directly on the hippocampus to induce translocation of protein kinase C in the CA3 region. Such an effect may be associated with the bifemelane-induced augmentation of the long-term potentiation in this region of the brain.

Animals↗

PubMed1990

Morphometrical studies on perinatal development of glomerular components in rat.

Perinatal development of rat glomerulus was studied morphometrically. The percentage volumes of the five glomerular components (epithelial cells, capillary, mesangium, glomerular basement membrane, and Bowman's space) were determined by point counting and the surface area of glomerular basement membrane per unit volume of glomerulus was done by intercept counting. Percentage volume of Bowman's space was significantly decreased between days 20 and 21 of gestation, indicating the rapid growth of glomerular tuft during the prenatal period. Though both the length of glomerular capillary per unit volume of glomerulus (Lv) and surface area of glomerular basement membrane per unit volume of glomerulus were gradually increased from fetal day 20 to neonatal day 3, remarkable increase in Lv was observed between fetal day 22 and neonatal day 1. This indicates that the rat glomerulus develops rapidly during this period to adapt to extrauterine environment after birth.

Animals↗

PubMed1990

Comparison of flow-resistive work load due to humidifying devices.

There are many kinds of humidifying devices. We evaluated six humidifiers from the viewpoint of AWLs. The AWL was obtained by calculating the area difference between pressure-volume tracings obtained without and with humidifiers. To examine the effect of pressure monitoring sites on AWL when a humidifier is placed, we measured AWL at three different pressure monitoring sites. The AWL was affected significantly by the pressure monitoring site for the ventilator. When a pressure monitor sensor was placed on the inspiratory limb between the inspiratory valve and humidifiers, the ventilator was not able to compensate for the pressure drop caused by impedance characteristics of the humidifier equipment. This resulted in significant inspiratory AWL on the patient. Thus, humidifying devices should be carefully selected from the viewpoint of not only humidifying capability but also AWL. Furthermore, we must recognize the importance of the pressure monitoring site for the ventilator.

Airway Resistance↗

PubMed1990

[A study on a design guide for detached houses with home-elevators for aged and physically handicapped persons].

The purpose of this paper is to extract the design guide of the detached houses with home-elevator for aged and physically handicapped persons, so, for 4 cases we investigated the composition of living spaces, living activities and dweller's evaluation. The main results are follows: (1) The aged and physically handicapped persons' room generally must be located at the 1st floor, but setting up the home-elevator house planning turns into more free. (2) Setting up the home-elevator, we can locate the aged and physically handicapped persons' room at the highest floor. In the case of town houses having few site areas, the highest floor has often good condition of the exposure to the sun and the view, so the aged and physically handicapped persons prefer the highest floor room. (3) In the aged and physically handicapped persons' houses, the corridor and the sanitary space get cold in winter, because those spaces are wide using the wheel chair and helping. So these houses need the floor heating. (4) In the aged and physically handicapped persons' houses, at the garage going in and out must be free without the difference in level, the space of the elevator hall must be secured fully turning the wheel chair, and at the garage the place of the outdoor wheel chair and the transfer space must be secured fully. (5) In the case of using home-elevator the noise is no problem. In opposition, the family members feel easy to hear the sound of home-elevator, because they can perceive the aged and physically handicapped persons' activities.

Aged↗

PubMed1990

[Dural arteriovenous malformation in the posterior fossa presenting with multiple intracerebral hematomas. Case report].

A 59-year-old female was hospitalized because of disturbance of consciousness and convulsive seizures. She had taken a hormonal drug for 15 months after breast cancer surgery. A computed tomography scan revealed multiple high-density areas in the left temporal and frontal and the right parietal lobes. Angiography showed a dural arteriovenous malformation (AVM) in the posterior fossa fed by the occipital and the middle meningeal arteries and draining into the transverse sinus. It also demonstrated occlusion of the left sigmoid sinus in the venous phase. She complained of headache in the occipital region and dizziness. On day 13, the left occipital artery was ligated and cut, and then abnormal arterial anastomoses around the lesion were coagulated. After surgery, clinical symptoms disappeared. The etiology of dural AVM is controversial, but in this case it is suspected that sinus thrombosis due to the drug caused the dural AVM. The authors discuss the etiology and treatment of dural AVM in the posterior fossa.

Arteriovenous Malformations↗

PubMed1990

Arteriovenous malformation associated with moyamoya disease--case report.

The authors report a case of moyamoya disease accompanied by arteriovenous malformation (AVM). Angiography demonstrated typical moyamoya vessels on the right and early changes of moyamoya disease on the left. A small AVM in the left frontal lobe supplied by a distal branch of the middle cerebral artery (MCA) was also revealed. The AVM was surgically resected simultaneously with contralateral encephaloaponeurotic synangiosis for the moyamoya vessels. One month after surgery, left MCA occlusion at the origin occurred probably due to hemodynamic changes after the resection of the AVM.

Adult↗