Search PubMed⌕ Search

Biomedical subjects

K Isobe

Publications and source records attributed to K Isobe.

At least 289 records · Page 16Linked to original sources
PubMed1987

Identification and characterization of a unique tumor-associated surface antigen on L1210 leukemia cells recognized by semisyngeneic antisera.

The tumor-associated surface antigen on L1210 leukemia cells was studied by immunofluorescence staining and immunoprecipitation. Anti-L1210 serum was prepared in BALB/c X DBA/2 F1 mice by priming with a hybrid of L1210 and human Lesch-Nyhan fibroblast cells and hyperimmunizing with L1210 leukemia cells. This hyperimmune serum was able to demonstrate specific surface fluorescence on L1210 cells, while the antiserum did not react with various mouse tumor cell lines, normal lymphoid tissues, or mitogen-activated lymphoid cells. The anti-L1210 serum immunoprecipitated a single polypeptide with a molecular weight of 90,000 from 125I-labeled L1210 cells. The expression of this antigen was enhanced by tumor-promoting agent and heat shock treatment. The biological significance of the L1210-specific cell surface antigen is discussed.

Animals↗
PubMed1987

A simple enzymatic differential assay for diamines, spermidine, and spermine in urine and blood.

This rapid, reliable enzymatic differential assay method for diamines (putrescine plus cadaverine), spermidine, and spermine in urine and blood is suitable for practical routine use and does not require special and expensive equipment. The method is based on a combination of the substrate specificities of two amine oxidases, i.e., polyamine oxidase from A. terreus and putrescine oxidase from M. rubens. Quinone dye, derived from hydrogen peroxide generated in each of three end-point reactions, is measured spectrophotometrically at 555 nm, and the amounts of the respective amines are simply calculated. Analytical recoveries and precisions are acceptable. The proposed method produces results which correlate with high-performance liquid chromatography. Twenty or more assays can be done within 3 hr by one technician.

Chromatography, High Pressure Liquid↗
PubMed1987

A rapid enzymatic assay for total blood polyamines.

We have designed a rapid, reliable enzymatic assay for total blood polyamines, as based on the combination of substrate specificity of polyamine oxidase (PAO) from Aspergillus terreus and putrescine oxidase (PUO) from Micrococcus rubens. Quinone dye, derived from hydrogen peroxide generated in the oxidation reaction, is measured spectrophotometrically at 555 nm, and total amounts of putrescine (Put), cadaverine (Cad), spermidine (Spd), and spermine (Spm) can be readily determined. The minimum detection limit is about 0.4 mumol/L whole blood. Bilirubin, hemoglobin, reducing substances, and anticoagulants show no apparent interference. Analytical recovery averaged 98.5%. Within-run and between-day precisions ranged from 1.02% (61.04 mumol/L) to 2.84% (13.07) and 1.54% (50.67) to 3.27% (14.74), respectively. Results obtained with this method and those by high-performance liquid chromatography (HPLC) (r = 0.955) or the enzymatic differential method (r = 0.944) correlated well. In our opinion, this method is superior to other assays being used to determine blood polyamines.

Adult↗
PubMed1987

Wavelength dependence of the geometric and structural photoisomerization of bilirubin bound to human serum albumin.

The two quantitatively important photoisomers in bilirubin metabolism during phototherapy are (ZE)-bilirubin and (EZ)-cyclobilirubin. We describe in vitro studies on the wavelength dependence for the geometric (delta 4Z, delta 15Z----delta 4Z, delta 15E) and structural (endovinyl cyclization) photoisomerization of bilirubin bound to human serum albumin by a high performance liquid chromatography method. For the geometric photoisomerization from (ZZ)-bilirubin to (ZE)-bilirubin, the most effective wavelength in vitro was 410 nm. For the structural photoisomerization, green light at 510 nm is the most efficient for causing cyclization of (ZZ)-bilirubin to (EZ)-cyclobilirubin via (EZ)-bilirubin and this may depend on a larger cross-section of (EZ)-bilirubin than (ZZ)-bilirubin in this spectral region and/or on a larger quantum yield for cyclization than geometric photoisomerization.

Bilirubin↗
PubMed1987

Effects of intravascular volume expansion on cerebral blood flow in patients with ruptured cerebral aneurysms.

To clarify the effect of intravascular volume expansion on cerebral blood flow (CBF) in patients after subarachnoid hemorrhage (SAH), we performed 55 pairs of regional CBF measurements using the xenon-133 inhalation method before and after volume expansion in 35 patients with ruptured cerebral aneurysms. CBF was calculated as the hemispheric mean value of the initial slope index. To accomplish volume expansion, we transfused 500 ml of 5% human serum albumin in half an hour. After volume expansion with albumin, the hemoglobin value decreased significantly (P less than 0.005). Volume expansion did not change the mean arterial blood pressure. During the first 2 weeks after SAH, CBF decreased significantly after volume expansion (P less than 0.005). During the 3rd week after SAH and subsequently to the 4th week after SAH, volume expansion produced no change in CBF. In patients with symptomatic vasospasm, CBF decreased significantly after volume expansion (P less than 0.005). In patients without symptomatic vasospasm, volume expansion produced no change in CBF. The results of this study suggest that increasing the intravascular volume above normal by volume expansion does not increase CBF or reverse symptomatic vasospasm.

Adult↗
PubMed1987

[Extracranial internal carotid occlusion and coexisting ipsilateral intracranial internal carotid aneurysm].

A rare case of extracranial internal carotid occlusion with a coexisting ipsilateral internal carotid aneurysm is reported. A 50-year-old male had a sudden onset of severe headache, vomiting and right motor weakness on May 14, 1984. Two days later the patient was transferred to our hospital. On admission he was alert but presented with nuchal rigidity and right moderate hemiparesis. He had an episode of a blunt head injury 12 years previously, but no history of hypertension, diabetes mellitus or cerebral stroke. A computed tomography revealed mild subarachnoid hemorrhage and mild ventricular dilatation. A cerebral angiography did not demonstrate any aneurysms but it revealed occlusion of the right internal carotid artery at the cervical bifurcation. The repeated angiography on May 31 disclosed a saccular aneurysm arising anteromedially at the level of the junction of the right posterior communicating artery and the internal carotid artery. The cervical internal carotid artery remained occluded at the same site. The middle cerebral artery was supplied through the well-developed posterior communicating artery, and the right anterior cerebral artery was supplied through the anterior communicating artery. Clipping of the aneurysm was attempted but it was forcibly trapped because of premature bleeding on June 5. The right V-P shunt was performed for the progressive ventricular dilatation on June 12. The patient was discharged with no paresis on June 20. It has been well known that the uni- or bilateral carotid occlusion, whatever the origins are, are often associated with cerebral aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Artery Diseases↗
PubMed1986

Establishment of a murine leukemia L1210-specific T-cell clone displaying novel in vivo anti-tumor activity.

The murine leukemia L1210-specific cytotoxic T-cell clone K7 was established by repeated antigenic stimulation of spleen cells of L1210-immune CD2F1 mice in long-term culture. K7 possessed L1210-specific cytolytic activity detectable by the 51Cr-release test, but lost its cytolytic activity about 100 days after initiation of culture (designated as clone K7L). Clone K7L retained its L1210-specific tumor-growth-inhibitory activity independently of culture supplementation with IL-2. K7L possessed the cell-surface antigenic phenotype of cytotoxic T cells, Thy-1+, Lyt-1-, Lyt-2+. This clone K7L displayed surprisingly strong activity in specifically inhibiting in vivo tumor growth of L1210 by day 5 in the peritoneal cavity of CD2F1 mice when injected together with 10(5) tumor cells (more than 90% inhibition at E/T = 5), and prolonged survival times of most of the mice for more than 60 days, whereas control mice inoculated with L1210 alone died on day 9-17. This unique in vivo anti-tumor activity was not correlated to the in vitro cytolytic activity. Nevertheless, bystander inhibitory effect on the growth of third-party tumor cells (P388) was not seen in mice injected with a mixture of L1210 and P388 together with K7L, suggesting that K7L inhibited L1210 growth by direct cell-to-cell interaction. Host cells such as X-irradiation (800R)-sensitive lymphocytes and Carrageenan-sensitive macrophages were not involved in the early growth inhibition of L1210 by K7L.

Animals↗
PubMed1986

The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method.

Unbound bilirubin is oxidized to nearly colourless substances in the presence of H2O2 or ethyl hydroperoxide and horseradish peroxidase. To predict the risk of kernicterus (degenerated yellow pigmentation of nerve cells), this principle has been widely utilized for estimating the concentration of unbound bilirubin in hyperbilirubinaemic serum. However, the serum contains polar geometric photoisomers of bilirubin. Therefore, to clarify the effect of bilirubin photoisomer concentrations on unbound-bilirubin concentration, the concentration of bilirubin and its photoisomer and of unbound bilirubin in samples obtained from experiments in vivo and in vitro were simultaneously and individually estimated by h.p.l.c. and the peroxidase method. During photoirradiation, both in vivo and in vitro, the serum polar (ZE)-bilirubin IX alpha concentration increased remarkably, but unbound-bilirubin values were not affected at all. However, during experiments in vitro, unbound bilirubin concentrations increased only when concentrations of the rather polar (EZ)- and (EE)-cyclobilirubin IX alpha increased considerably in a human serum albumin-bilirubin solution irradiated with blue light. Thus it is concluded that unbound-bilirubin concentrations, and consequently the initial rate of the peroxidase reaction, is not accelerated by the increase in either (ZE)-bilirubin or (EZ)-cyclobilirubin concentration within the clinically observed range.

Bile Pigments↗
PubMed1986

T cell independent Thy-1 allo-antibody response with the use of transgenic mice.

We have introduced a mouse Thy-1.1 gene into the germline of Thy-1.2 mice. The introduced gene was shown to be expressed at very high levels in thymocytes when compared with the endogenous gene. Transgenic thymocytes were shown to evoke a higher than normal primary anti-Thy-1.1 antibody response in plaque-forming cell (PFC) assays. This result suggests that a direct quantitative interaction of the Thy-1 antigen activates the B cell response.

Animals↗
PubMed1986

Wavelength-dependence of the relative rate constants for the main geometric and structural photoisomerization of bilirubin IX alpha bound to human serum albumin. Demonstration of green light at 510 nm as the most effective wavelength in photochemical changes from (ZZ)-bilirubin IX alpha to (EZ)-cyclobilirubin IX alpha via (EZ)-bilirubin.

The kinetics for the quantitatively important reaction: (Formula: see text) that is, the photochemical interconversion between bilirubin and its geometric and structural photoisomers bound to human serum albumin in aqueous solution when various wavelengths of monochromatic light were used, were assayed by h.p.l.c. In order to clarify the wavelength-dependence of the relative rate constants in the individual steps, a light-source with a half-bandwidth of 10 nm was used at increments of 20 nm, in the range from 410 nm to 550 nm. We describe for the first time studies on the wavelength-dependence of rate constants in geometric and structural photoisomerization reactions in vitro of (ZZ)-bilirubin or (EZ)-bilirubin bound to human serum albumin, especially the relative rate constants of cyclization of (EZ)-bilirubin into (EZ)-cyclobilirubin. Because studies in vitro have demonstrated that the wavelengths from 350 to 450 nm are mutagenic, the results obtained indicated that the safest and ideal light-source for phototherapy is green light of 510 nm, which keeps (ZE)-bilirubin concentrations as low as possible, as shown by a maximal value of k2 at 510 nm and a relatively low value of k1 at 510 nm. This light-source still ensures the substantial absorption of (ZZ)-bilirubin, which is the precursor of (EZ)-bilirubin, the intermediate in (EZ)-cyclobilirubin formation and, furthermore, as shown by the maximal value of k5 and a considerable value of k4 at 510 nm, promotes the cyclization of (EZ)-bilirubin derived from (ZZ)-bilirubin even though k3 at 510 nm also shows a peak value.

Bilirubin↗
PubMed1986

Aberrancy in immunogenicity and cell-surface expression of H-2 antigens on erythrocytes.

Immunogenicity for T cell-independent B-cell response assessed by splenic plaque-forming cell (PFC) response and cell-surface expression measured by laser flow cytometry of various class I H-2 antigens on mouse red blood cells (RBC) were compared. It was found that the order of magnitude of both immunogenicity and cell-surface expression on RBC is H-2Dd much greater than H-2Db greater than H-2Kd, H-2Kb. Furthermore, H-2d public antigens and H-2Ld antigens were neither immunogenic nor easily demonstrable on RBC. These findings contrasted with poor immunogenicity for PFC response (Nakashima et al. 1982, 1983) and proportionally strong expression of H-2 antigens on lymphoid cells. Immunogenicity and cell-surface expression of H-2Dd antigen on RBC were not shown to be controlled by the action of genes outside H-2D. It was therefore suggested that a number of H-2 antigens, including H-2Kd private, H-2Kb private, and H-2d public specificities are at least functionally defective on RBC. This is possibly due to the structural characteristics of the antigens. Since immunogenicity and cell-surface expression were in parallel, the expression of H-2 antigens on RBC must be dictated by a subset of B cells whose activity was assessed by PFC response. This finding supports the view that the H-2 molecules display a new category of activity which is different from their ability to activate T cells and depends on their expression on RBC.

Animals↗
PubMed1986

An assay for ribonuclease activity, based on ultraviolet absorption of RNA hydrolysate, using phosphotungstic acid.

In the method for the determination of ribonuclease activity that depends on the ultraviolet absorption of the RNA hydrolysate, the uranium reagent (25% perchloric acid solution containing 0.75% uranyl acetate) is commonly used for the efficient precipitation of the unhydrolyzed RNA. However, this reagent is always contaminated by the presence of radioactive isotopes. Radioactive uranium is one of the substances used for atomic nuclear fuel and therefore, at least in Japan, the use of uranium compounds requires permission from the government. We tried to find another efficient and non-radioactive precipitant of RNA to replace the uranium reagent, and have developed a phosphotungsten reagent (25% perchloric acid solution containing 0.75% phosphotungstic acid plus 0.6% bovine serum albumin solution) which functions as efficiently as the uranium reagent in the precipitation of RNA. A cell-free crude extract of Dictyostelium discoideum was used as the source of ribonuclease.

Chemical Precipitation↗
PubMed1986

Augmentation of antibody responses of mice to inhaled protein antigens by simultaneously inhaled bacterial lipopolysaccharides.

Serum antibody responses of mice to repeatedly inhaled protein antigens such as bovine serum albumin and ovalbumin, plus or minus bacterial lipopolysaccharide (LPS) in the form of an aerosol were studied. Results showed that the levels of responses to inhaled protein antigens varied, depending on the mouse strain-antigen combination and that LPS inhaled simultaneously with the antigens definitely augmented the responses which were not otherwise very high. LPS extracted from Klebsiella O3 (LPS-K) but not LPS from Escherichia coli O55 (LPS-E), which was inhaled at the time of initial inhalation of antigen, significantly intensified the priming for the secondary antibody response to the antigen subsequently inhaled. Both LPS-K and LPS-E, however, definitely acted to augment the response when they were inhaled repeatedly together with the antigen. Oral administration of antigen or antigen plus LPS-K did not induce any detectable antibody response in our experiment, ruling out the possibility that the antigen and LPS stimulated the immune system via alimentary canal rather than via lung. Tissue distribution of the radioactivity soon after inhalation of 131I-labeled antigen and decay speed of the radioactivity were not significantly changed by LPS-K inhaled simultaneously. This suggested that the augmentation of responses was not mediated by the action of LPS to modulate the air-blood barrier against the entry of antigen via lung. All the results prove for the first time that inhaled LPS displays a definite adjuvant action on antibody responses to inhaled antigens.

Adjuvants, Immunologic↗
PubMed1986

Metabolism of bilirubin and its photoisomers in newborn infants during phototherapy.

Bilirubin and its photoisomers in the biological fluids of a hyperbilirubinaemic newborn infant before and during phototherapy were analyzed by a recently improved HPLC method. In the serum, the percentages of (EZ)- and (ZE)-bilirubin in the total bilirubin concentration before phototherapy were approximately 10% and on average increased over 1.5-fold at 2 h after initiation of phototherapy. The percentage of the (EZ)-cyclobilirubin in the serum bilirubin was under 1%. In the bile, the mean concentration of (ZZ)-bilirubin, derived mainly from (ZE)-bilirubin, nearly tripled during phototherapy. The (EZ)-cyclobilirubin concentration in the bile was very low before phototherapy, increased nearly ten-fold at 3 h after initiation of phototherapy, and was 5- to 6-fold as high as that of (ZZ)-bilirubin. In the urine, upon exposure to light, the urinary concentration of (EZ)-cyclobilirubin is apparently equivalent to half of the biliary concentration of (ZZ)-bilirubin and one-fifth of that of (EZ)-cyclobilirubin. It was concluded that during phototherapy of neonatal hyperbilirubinaemia the structural photoisomer [(EZ)-cyclobilirubin] predominates considerably over the geometric photoisomer [(ZE)-bilirubin].

Bilirubin↗
PubMed1986

[Fundamental study of imipenem/cilastatin sodium in obstetrics and gynecology].

Following results were obtained from drip intravenous administration of imipenem/cilastatin sodium (MK-0787/MK-0791) (500 mg/500 mg) by measuring concentration of MK-0787 in uterine arterial plasma, cubital venous plasma, oviduct, ovary and several sites in uterine tissue in cases of simple hysterectomy, and pelvic cavity fluid in cases of radical operation. Cervix uteri, portio vaginalis, myometrium showed higher concentration among various uterine tissues in any time after the end of administration. In cases of radical operation, the pelvic cavity fluid showed 6.6 approximately 7.8 micrograms/ml at 5 hours after the end of administration. In the field of obstetrics and gynecology, it was considered that MK-0787/MK-0791 has good efficacy in infections especially caused by Gram-positive aerobic bacteria.

Adult↗
PubMed1986

[Regional cerebral blood flow (rCBF) in patients with ruptured cerebral aneurysm: site of aneurysm and rCBF].

To investigate the relationship between the site of ruptured cerebral aneurysm and rCBF, 92 measurements of rCBF were conducted in 57 patients with ruptured cerebral aneurysm. Excluded from this study were patients with multiple aneurysms, intracerebral hematoma, and/or hydrocephalus. Twenty-four patients had the anterior communicating aneurysm (A-com), 20 patients had the internal carotid aneurysm (ICA), and 13 patients had the middle cerebral aneurysm (MCA). All patients underwent unilateral fronto-temporal craniotomy for clipping of the aneurysm and their rCBF measurements, using the xenon-133 inhalation method, were performed in the first three weeks after surgery. In each rCBF measurement, the hemispheric mean value of initial slope index (meanISI) was calculated in both cerebral hemispheres, that is, in the cerebral hemispheres ipsilateral and contralateral to craniotomy. The authors defined the "symmetry index of the meanISI (%): symmetry index" as the ratio of the meanISI in the cerebral hemisphere ipsilateral to craniotomy compared to the meanISI in the cerebral hemisphere contralateral to craniotomy. There was no significant relationship between the site of aneurysm and the meanISI in both hemispheres, and this result suggests that the site of aneurysm makes no difference in the incidence of vasospasm. In the postoperative first week, the "symmetry index" was 91.2 +/- 7.4% in MCA, 95.3 +/- 4.1% in ICA, and 97.9 +/- 8.2% in A-com; that is, MCA had significant asymmetry of meanCBF compared with A-com (p less than 0.05). In the second and third postoperative weeks, there was no significant relationship between the site of aneurysm and the asymmetry of meanCBF.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrovascular Circulation↗
PubMed1985

Depression of afferent arc of the in vivo cytotoxic T-cell immunity by bacterial lipopolysaccharides.

The afferent arc of the in vivo cytotoxic T-cell immunity assessed by second set rejection of ascitic allogeneic tumors was shown to be depressed by bacterial lipopolysaccharide (LPS) that was administered simultaneously with or 1 day before injection of allogeneic spleen cells as stimulators. Two different LPSs from Escherichia coli O55 and Klebsiella O3 displayed similar activities whereas dextran sulfate, concanavalin A, or poly A:U was not effective. Stimulator activities of allogeneic cells was not directly modified by LPS. Any definite suppressor activity on afferent or efferent arc of the T-cell response was not demonstrable in mice receiving LPS and allogeneic cells. Further, the LPS effect for immune depression was not diminished by whole body X-ray irradiation to the recipient at 300 R, which ablated the B-cell reactivity to LPS for polyclonal activation, or by treatment of the recipient with carrageenan, a known toxic agent to macrophages. It was suggested from these results that LPS suppresses the cytotoxic T-cell immunity by modulating responder T cells to be temporarily refractory to the allogeneic stimulus rather than by activating suppressor cells such as radiation-sensitive lymphocytes and carrageenan-sensitive macrophages.

Animals↗