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Biomedical subjects

T Ohno

Publications and source records attributed to T Ohno.

At least 667 records · Page 37Linked to original sources
PubMed1988

Expression of tobacco mosaic virus RNA in transgenic plants.

Tobacco mosaic virus (TMV) is a message-sense, single-stranded RNA virus that infects many Solanaceae plants. A full-length cDNA copy of TMV genomic RNA was constructed and introduced into the genomic DNA of tobacco plants using a disarmed Ti plasmid vector. Transformed plants showed typical symptoms of TMV infection, and their leaves contained infectious TMV particles. This is the first example of the expression of RNA virus genomic RNAs in plants.

Base Sequence↗
PubMed1988

Biochemical studies on prolidase in sera from control, patients with prolidase deficiency and their mother.

Prolidase activity in serum from normal subjects and the mother of two patients was readily detected without adding Mn2+ to the assay, and the activity was increased by addition of Mn2+ to the assay or preincubation with Mn2+. However, the activity in serum from patients with prolidase deficiency against gly-pro, leu-pro and val-pro could not be detected irrespective of Mn2+ conditions and activity against met-pro, ala-pro and phe-pro also showed a marked reduction compared to controls. Both normal and the patients' mother's prolidase activity against gly-pro was reduced about 20% at 60 degrees C compared to the activity at 37 degrees C, but the addition of Mn2+ at 55 degrees C increased the activity about 1.8-fold, whereas prolidase activity of patients could not be increased by the addition of Mn2+. The addition of Co2+ increased prolidase activity in serum from control and the patients' mother but did not increase the heat stability. These results indicate that prolidase in serum from patients with prolidase deficiency is altered rather than markedly reduced in amount.

Dipeptidases↗
PubMed1988

Biochemical analysis of inhibitory effects of a lymphokine suppressive B-cell factor on the activation process of resting B cells.

Suppressive B-cell factor (SBF) is elaborated by FcR gamma (Fc receptor for IgG)-bearing small, resting B cells after the stimulation of immune complexes and is known to inhibit humoral immune responses by acting on resting B cells. In order to elucidate where and how SBF interferes with B-cell activation in the course of transmembrane signaling, we examined the effect of SBF on the several sequential events which B cells undergo after crosslinking surface immunoglobulin (sIg). Hyper-Ia expression, plasma membrane depolarization, and activation of phosphatidylinositol (PI) hydrolysis of resting B cells, all of which were induced by the stimulation with anti-mu antibody, were significantly suppressed by the pretreatment of cells with SBF. However, SBF had no effect on the intracytoplasmic cyclic AMP level of either activated or resting B cells. Another inhibitory effect of SBF on the activation process of resting B cells by anti-mu antibody was to suppress the transient elevation of intracytoplasmic free Ca2+ only in the initial phase after triggering with anti-mu antibody. This seems to be due to a decrease in the release of inositol triphosphate into the cytoplasm by suppressing the activation of PI hydrolysis. Considering all the data, the suppressive effect of SBF on the transmembrane signaling by sIg crosslinking is ascribed to the selective suppression of the activation of PI hydrolysis. This provides a concept on a molecular basis that feedback regulation of humoral immune response is, at least partly, regulated by SBF.

Animals↗
PubMed1988

Computer graphic analysis of antigenic sites on the insulin molecule.

Antigenic sites on a protein have been predicted by the measurement of hydrophilicity values. We have compared this approach to the use of atomic temp factors to predict the antigenic sites on insulin. These predictions were based upon computer assisted analysis of X-ray crystallography data. The results demonstrate that the hydrophilic sites A6, B19, B23, B24, and B26 are not on the surface of the molecule and therefore are not potential antigenic determinants. Thus, hydrophilicity values alone are not sufficient to predict antigenic sites. In contrast, atomic temp factors were more predictive of antigenicity. These findings may explain why anti-insulin antibodies are less likely to develop against certain hydrophilic sites.

Animals↗
PubMed1988

Spinal cord compression by epidural metastases. Fibrosarcoma experiments in rats.

Morphologic changes were studied in 43 rats that were paralyzed by an epidural fibrosarcoma inoculated through the spinous process. By this technique, of 29 rats examined radiographically, the tumor destroyed vertebral bone in 22. Changes of the cord in the early stage of paralysis were specially analyzed by Marchi's stain and microangiograms. In compromised cord segments in the early stage, extravasation of contrast medium was observed in the gray matter and the dorsal funiculus; and in the dorsal funiculus just proximal or distal to the compressed portion, hemorrhagic areas were present. Ascending degenerated fibers in the dorsal funiculus, which were derived from the degenerated posterior nerve root or the degeneration of the dorsal funiculus in the compressed segments, were characteristically detected in rats in the early stages. In the advanced stages a transverse cord lesion was observed at the involved level. Based on the present analyses, to prevent more advanced damage to the spinal cord, the tumor should be removed at an early stage that clinically coincides with the period when radicular signs appear.

Animals↗
PubMed1988

Gastric surface epithelial cell damage induced by restraint and water-immersion stress in rats. Protective effects of 16,16-dimethyl-prostaglandin E2.

The time course of gastric mucosal surface epithelial cell damage and macroscopically visible lesions in response to restraint and water-immersion stress (22 degrees C) in rats was examined, and the prophylactic effects on it of 16,16-dimethyl-prostaglandin E2 (dmPGE2) were compared with those of papaverine, timoprazole, and atropine. The stress produced surface epithelial cell damage prior to visible lesion, the former increasing in severity with time and reaching a plateau 60 min later, by which time exfoliation of surface epithelial cells was observable along the mucosal folds. In contrast, macroscopically visible lesions appeared 2 h after stress, and severity continued to increase with time. Pretreatment injections (s.c.) of dmPGE2 (3 and 30 micrograms/kg), papaverine (100 mg/kg), and atropine (1 mg/kg) protected the surface cells against stress-induced (1 h) damage, and inhibited visible lesion formation after 4 h stress. Timoprazole (30 mg/kg s.c.) did not protect the surface cells, but did markedly inhibit visible lesion formation. DmPGE2, papaverine, and atropine, but not timoprazole, inhibited stress-induced increases in gastric contractions. DmPGE2, timoprazole, and atropine, but not papaverine, inhibited acid secretion in stress conditions. These results indicated that stress induced damage to the gastric mucosa within 1 h due to increased gastric contractions, and the surface epithelial cell damage developed into macroscopically visible lesions in the presence of acid, and that dmPGE2 protected the surface epithelium against stress-induced damage probably by inhibiting gastric contractions.

16,16-Dimethylprostaglandin E2↗
PubMed1988

Immunogenotypes of lymphoid malignancies; the rearrangement of T cell receptor beta chain gene can occur before the gamma chain gene rearrangement.

Immunoglobulin (Ig) and T cell receptor (TcR) gene rearrangements were analyzed in 101 cases of lymphoid malignancies in association with a surface phenotype study. In leukemias/lymphomas with mature phenotype, there is a good correlation between phenotypes and genotypes. However, in leukemias/lymphomas with immature phenotype, we found many discordances between phenotypes and genotypes, suggesting the stochastic nature of hematopoietic cell differentiation at the early stage. As for TcR beta and gamma chains, the rearrangement of gamma chain gene is considered to occur slightly prior to that of beta chain gene. However, we observed a mature T cell malignancy, adult T-cell leukemia, with rearranged beta chain gene and germ line gamma chain gene, showing the possible existence of another pathway of T cell differentiation.

Cell Differentiation↗
PubMed1988

Rapid and correct identification of intestinal Bacteroides spp. with chromosomal DNA probes by whole-cell dot blot hybridization.

A dot blot hybridization procedure with 32P-labeled whole chromosomal DNA of the type strains as probes was developed as a rapid and simple method for identification of intestinal Bacteroides species. Bacterial cells were fixed onto membrane filters by slight suction, treated with 0.5 N NaOH, and hybridized with these probes. Of 65 Bacteroides strains isolated from 19 human fecal specimens, which were identified as B. fragilis, B. thetaiotaomicron, B. ovatus, B. caccae, B. uniformis, B. stercoris, B. vulgatus, B. distasonis, and B. merdae by conventional phenotypic characterization, 62 (95%) were correctly identified with this hybridization procedure.

Adult↗
PubMed1988

Developmental hemodynamic changes in rat embryos at 11 to 15 days of gestation: normal data of blood pressure and the effect of caffeine compared to data from chick embryo.

We attempted to measure arterial blood pressure of the rat embryo. The embryo was excised within the uterus and immersed in Hanks' solution at 37 degrees C. The uterus wall and yolk sac were opened to expose the umbilical vessels. The umbilical artery was punctured with a glass micro-pipette, and blood pressure was measured by using a servo-null micro-pressure system. The mean blood pressure was 0.27 +/- 0.05 mm Hg in the embryo at the 11th day of gestation (n = 7), 0.48 +/- 0.03 mm Hg in the 12-day embryos (n = 19), 1.3 +/- 0.08 mm Hg in the 13-day (n = 11), and 2.6 +/- 0.1 mm Hg in the 15-day embryos (n = 10). Heart rate was 84 +/- 11 in 11-day, 122 +/- 3 in 12-day, 192 +/- 7 in 13-day, and 198 +/- 5 in 15-day embryos. These parameters were stable within 10 min after the excision. A comparison of the data with those of the chick embryo of comparable developmental stages revealed that the blood pressure was lower in 11- and 12-day rat embryos than in the chick embryo of Hamburger-Hamilton stages 18 and 21, but this was reversed in the later stages. In the stage 21 chick embryo, intravenous administration of caffeine (60 +/- 9 mg/kg embryo weight) induced an increase in blood pressure by 11 +/- 3% (n = 8), but did not result in a significant increase in dorsal aortic blood flow (6 +/- 6%, n = 9) or in heart rate. In contrast, caffeine (62 +/- 3 mg/kg) increased the heart rate by 8 +/- 2% (n = 10) without changing the blood pressure in the rat embryo of day 12. The velocity of blood flow in the truncus was measured by a pulsed Doppler flowmeter. Caffeine injection increased the mean velocity by 21 +/- 8%). Herein we indicate that measurement of blood pressure in the rat embryo is feasible, but with some limitations, and that there may be qualitative hemodynamic differences between the rat and chick embryos.

Animals↗
PubMed1988

Comparative analysis of lymphocyte phenotypes between carriers of human immunodeficiency virus (HIV) and adult patients with primary immunodeficiency using two-color immunofluorescence flow cytometry.

A variety of phenotypic abnormalities of peripheral blood lymphocytes from 8 HIV-carriers (HIVC), 6 patients with common variable immunodeficiency disease (CVID), and 13 patients with selective immunoglobulin deficiency (SIgD) were compared using two-color flow cytometry. There was a close resemblance in phenotypic abnormalities between HIVC and the patients with CVID; i.e., increases in CD8+CD11-, Leu7+CD16- and CD3+DR+ cells, and decreases in CD4+Leu8+, CD4+Leu8-, Leu7+CD16+ and Leu7-CD16+ cells. The increase in CD3+DR+ cells was due to an increase in CD8+DR+ cells. The CD4/CD8 ratio was inverted in both groups. A strong correlation coefficient (CC) was found only between the CD4/CD8 ratio and CD4+Leu8+ cells in HIVC, while CC was also high between the CD4/CD8 ratio and CD8+CD11- cells in CVID. The phenotypic abnormalities of the patients with SIgD were various and no significant difference was found against the control, except for an increase in CD4+Leu8+ cells and a decrease in CD4+Leu8- cells, which suggests heterogeneity of immunological deficits in this group. In severe immunodeficiency, ineffective killer cells appeared to be induced as a result of an adaptive change involved in recurrent or persistent viral infections, and Leu8 molecule may be concerned in the susceptibility of CD4+ cells to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Soluble interleukin-2 receptors in the serum of patients with chronic renal failure.

The levels of soluble form of the interleukin-2 receptor (sIL-2R) were evaluated in the peripheral blood of 29 patients with chronic renal failure (CRF) using enzyme-linked immunosorbent assay. All patients had undergone hemodialysis and the mean (+/- S.D.) BUN was before hemodialysis was 80.9 +/- 22.4 mg/100 ml. The mean level of sIL-2R was 1146 +/- 258 U/ml, which was significantly higher than the level (288 +/- 118 U/ml) in 12 individuals with a normal BUN level (p = 0.01). In patients with CRF, the elevated sIL-2R level was not influenced by hemodialysis, and not correlated with creatinine or beta 2-microglobulin levels. The kidneys may play an important role in the catabolism of serum sIL-2R. The elevated sIL-2R level may be related to compromised immunoregulation in CRF.

Biomarkers↗
PubMed1988

Effect of immunoglobulin preparation on course of AIDS-related complex (ARC).

Relatively low dose treatment (150 mg/kg, once per two weeks) of a intravenous immunoglobulin (IVI) preparation has shown a beneficial effect on CD4/CD8 ratio and CD4 cell counts in two patients with AIDS-related complex (ARC). Since ARC generally progresses to AIDS with a marked reduction of CD4 cells or a marked inversion of CD4/CD8 ratio, this type of IVI treatment seems to be effective for obstructing or at least delaying the progression from ARC to AIDS.

AIDS-Related Complex↗