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Biomedical subjects

K Ogata

Publications and source records attributed to K Ogata.

At least 379 records · Page 21Linked to original sources
PubMed1987

Proliferating cell nuclear antigen (PCNA)/cyclin in activated human T lymphocytes.

Proliferating cell nuclear antigen (PCNA), also called cyclin, is an intranuclear polypeptide whose synthesis reaches its maximum during the S-phase of the cell cycle. PCNA is expressed in several kinds of proliferating cells, one of which is the mitogen-stimulated human peripheral blood lymphocyte. PCNA expression increases from the late G1 phase through the S-phase of the cell cycle. This study is focused on the regulation of PCNA expression during the G1 phase of human T lymphocytes and on the relationship between PCNA expression and the rate of T cell proliferation. Special use is made of human autoantibodies to PCNA and the development of flow cytometry to label this intranuclear polypeptide. Unstimulated purified human peripheral blood T cells were PCNA negative. T cells treated with monoclonal antibody (64.1) to the CD3 complex expressed receptors for IL 2 but did not express PCNA until exogenous IL 2 was added to the culture. PCNA expression as well as the entry of the cells into S-phase could be inhibited by IL 2 receptor antibodies. Transferrin receptors were expressed only in T cells that were stimulated with both 64.1 and exogenous IL 2. Transferrin receptors were detectable before the cells expressed PCNA. Thus, the onset of PCNA expression is a phase in cell proliferation that follows transferrin receptor expression but preceded DNA synthesis. Drugs like dexamethasone and cyclosporin, which affect the early part of G1, inhibited PCNA expression; whereas cytarabine (ara-C) and hydroxyurea, which affect the S-phase and prevent DNA synthesis, did not block PCNA expression. There was a close correlation between the number of PCNA-positive cells and the number of S-phase cells in unperturbed T cell cultures. The highest level of PCNA expression was seen in cells that were in the first cycle after stimulation. The results show that PCNA expression is regulated by a signal after IL 2 binding and that PCNA labeling is a precise indicator for human T cells that are committed to DNA synthesis. Comparing these results with previous observations on the expression of some other activation-associated antigens, we suggest that the onset of PCNA expression represents a discrete step in T cell activation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Nucleotide sequence of cloned cDNA specific for rat ribosomal protein L31.

A cDNA clone, specific for rat ribosomal protein L31, was isolated by hybrid-selected translation from a cDNA library made for 8-9-S poly(A)-rich RNA from regenerating rat liver. The nucleotide sequence of the cDNA was determined. It consists of 25 base pairs from the 5' leading sequence, the entire coding sequence of 378 base pairs and the 3' trailing sequence of 36 base pairs besides the poly(A) tail. The primary structure of protein L31 was deduced from the nucleotide sequence. It consists of 124 amino acids with a relative molecular mass of 14,331. The calculated amino acid composition is consistent with the reported composition determined for the hydrolysate of L31. The amino acid sequence showed marked homology with that of yeast ribosomal protein L34.

Amino Acid Sequence↗
PubMed1987

Cytomegalovirus infections in adult T-cell leukemia patients.

Cytomegalovirus (CMV) infection frequently occurred in patients with malignant lymphoma of T-cell origin, especially with adult T-cell leukemia (ATL). This was evidenced by histopathological examination at autopsy, isolation of CMV, and detection of CMV antibodies that indicate recent or active infection. Cellular immune response was suppressed in most ATL patients when examined by skin hypersensitivity reaction to purified protein derivatives (PPD), streptococcal antigens (SuPs), and phytohaemoagglutinin (PHA). None of the CMV-positive patients reacted to them. Thus, the presence of tumor cells of T-cell origin and the absence of skin hypersensitivity reaction seem to be risk factors for CMV infection. Each CMV isolate exhibited unique DNA fingerprints, suggesting that cross-infection of CMV did not occur among the ATL patients on the same ward.

Antibodies, Viral↗
PubMed1987

Inhibition of nuclear DNA synthesis by an autoantibody to proliferating cell nuclear antigen/cyclin.

Proliferating cell nuclear antigen (PCNA) is expressed in the nuclei of proliferating cells, but is not detected in resting cells. The kinetics of PCNA expression suggest that it is associated with a phase preceding active DNA synthesis. DNA synthesis is under cytoplasmic control, and there is a cytoplasmic protein, ADR (activator of DNA replication), that induces DNA synthesis in isolated quiescent nuclei. We now report that a human antibody preparation monospecific for PCNA, but not two monoclonal antibodies directed against different epitopes on PCNA, can inhibit the ability of ADR to induce DNA synthesis in isolated quiescent nuclei. This effect is not due to inhibition of DNA polymerase alpha activity. Thus, the anti-PCNA antibody exerts its effect either by directly influencing the initial interaction of ADR with the nucleus, or by inhibiting subsequent synthetic events.

Antigen-Antibody Reactions↗
PubMed1987

Monoclonal antibodies to a nuclear protein (PCNA/cyclin) associated with DNA replication.

Two hybridomas producing monoclonal antibodies to proliferating cell nuclear antigen. (PNCA)/cyclin were generated from spleen cells of BALB/c mice immunized with purified PCNA from rabbit thymus. The specificity of the monoclonal antibodies (19A2 and 19F4) was established by showing that they reacted in enzyme-linked immunosorbent assay (ELISA) with purified PCNA. Furthermore, they reacted in one-dimensional (ID) gel immunoblots with a 36 kD polypeptide which also reacted with human autoantibodies from lupus patients. Both monoclonals also recognized the nuclear polypeptide cyclin in two-dimensional (2D) gel immunoblots of HeLa cell proteins. Epitopes recognized by 19A2 and 19F4 were analysed by competitive inhibition test using a modified ELISA. The data suggested that the epitopes were closely related, but not identical. The data with human auto-antibodies were more difficult to interpret, although it suggested that some human anti-PCNA may share epitopes with 19A2 and 19F4, but in addition recognize different epitopes on the PCNA molecule.

Animals↗
PubMed1987

Fibers supplying the laryngeal musculature in the cranial root of the rabbit accessory nerve: nucleus of origin, peripheral course, and innervated muscles.

The location of the rabbit laryngeal motoneurons whose axons traverse the cranial root of the accessory nerve was studied with injection of HRP or nuclear yellow into the laryngeal muscles in combination with the intracranial severing of either the rootlets of the vagus nerve or those of the cranial root. The motoneurons were located in the diffuse cell group that forms a subnucleus occupying the caudal two-thirds of the nucleus ambiguus and sending fibers to the inferior laryngeal nerve. The caudal one-third of the diffuse cell group supplying the lateral cricoarytenoid muscle, was occupied only by these motoneurons, whereas in its rostral two-thirds, they were intermingled with motoneurons having axons that traversed the vagal rootlets. The thyroarytenoid and posterior cricoarytenoid motoneurons are present in the rostral two-thirds of the diffuse cell group; axons of the former traversed the rootlets of the cranial root, and of the latter traversed the vagal rootlets. On the other hand, the medial scattered cell group, located in the rostral one-third of the nucleus ambiguus and sending fibers to the cricothyroid muscle via the superior laryngeal nerve, contained only motoneurons with axons traversing the vagal rootlets. The above findings clarified that fibers of the cranial root enter the inferior laryngeal nerve after joining the vagus, and then reach the adductor muscles for the vocal fold, with their neurons of origin in a caudal portion of the nucleus ambiguus. The vagal rootlet fibers, with their neurons of origin situated more rostrally in the nucleus, innervate the tensor and abductor muscles via the superior and inferior laryngeal nerve, respectively.

Accessory Nerve↗
PubMed1987

Localization of rabbit laryngeal motoneurons in the nucleus ambiguus.

The localization of rabbit laryngeal motoneurons in nucleus ambiguus was investigated using injection of a fluorescent labeling substance, i.e., nuclear yellow, into the individual laryngeal muscles. The nucleus ambiguus of the rabbit comprises four subnuclei, CoG, SGm, SGl, and DiG. The CoG is a group of compactly arranged neurons, and is situated in the rostral one-half of the nucleus. The SG, situated in its rostral one-third, is scattered around the CoG, with a subdivision into SGm and SGl. These subdivisions are medial and lateral to the CoG, respectively. The DiG is formed by diffusely arranged neurons, and is located in the caudal two-thirds of the nucleus. All labeled motoneurons were found in the ipsilateral nucleus ambiguus. The motoneurons supplying the cricothyroid muscle, which is innervated by the superior laryngeal nerve, were present in the SGm, with a clear rostralward segregation from the other motoneurons. The motoneurons supplying the muscles innervated by the inferior laryngeal nerve were located in the DiG, where they displayed a rostrocaudal myotopical arrangement in the order posterior cricoarytenoid, thyroarytenoid, and lateral cricoarytenoid. The posterior cricoarytenoid motoneurons were intermingled with the thyroarytenoid motoneurons in the rostral two-thirds of the DiG, and the former tended to be concentrated more rostrally than the latter. The lateral cricoarytenoid motoneurons were confined to the most caudal one-third of the DiG.

Animals↗
PubMed1987

Restoration of Fc receptor-mediated desensitization of superoxide generation in human PMN by PMA.

The superoxide (O2-) generating activity of human polymorphonuclear leukocytes (PMN) was suppressed more than 50% compared with control cells by preincubation of the cells with soluble immune complexes (Fc receptor-mediated desensitization). The suppression was observed when wheat germ agglutinin (WGA) or N-formyl-L-methionyl-L-leucyl-phenylalanine (fMLP) was used as stimuli for O2- generation. However, the desensitized cells could produce as much O2- as control cells when they were stimulated with phorbol myristate acetate (PMA). The desensitized cells were pre-exposed to a small dose of PMA for a short period (2-3 min). By this procedure, the activity of the cells for WGA or fMLP induced O2- generation was almost completely restored. Similarly, the inhibitory effect of 3'-deazaadenosing on WGA, fMLP or immune complexes (IC) induced O2- generation was abolished by the short-term pre-exposure of the cells to a small dose of PMA.

Antigen-Antibody Complex↗
PubMed1987

Carpal tunnel syndrome in chronic renal dialysis patients: clinical evaluation of 62 hands and results of operative treatment.

A prospective study was performed on 62 hands in 45 consecutive patients on chrome dialysis carpal tunnel syndrome developed within an average of 116 months after formation of the arterio-venous fistula. We measured the intra-carpal canal pressure by the wick catheter technique and performed neurography. At operation, a markedly thickened transverse carpal ligament was usually found. A pneumatic tourniquet was applied in all except three cases, whose functioning fistulae were made of implants, but no complications such as obturation of the fistulae occurred. Thirty-three (76.7%) of 43 cases had good results. Full recovery of sensibility was obtained in all hands in which symptoms had been present for less than two years. There was no benefit from operation in two patients (4.7%), both of whom had symptoms for more than two years.

Adolescent↗
PubMed1987

Electric inhomogeneity in membranes of Characean internode influenced by light/dark transition, O2, N2, CO2-free air and extracellular pH.

The electric membrane potential as functions of position and time of Characean internode has been studied using a modified water-film electrode technique. Between the low-conductance hyperpolarized region (called the H-region or acidic region) and the high-conductance depolarized region (D-region), there is a difference in the direction of responses to light-off and -on stimulations. In darkness the membrane potential becomes hyperpolarized in the D-region, whereas it is depolarized in the H-region at the steady state. The potential difference between D- and H-regions, delta Vm, is increased by exposure to pure O2, N2, or CO2-free air. When the amount of water surrounding the internode is limited, the formation of an electric pattern occurs rapidly. In contrast, the recovery is delayed. The membrane potential of the D-region is sometimes hyperpolarized significantly with lowering of the extracellular pH to 7.5, while the potential of the H-region is slightly depolarized. This seems to be an all-or-none type response. However, the electric profile is always homogenized with the pH of 6.8. Thus, the pH around 7.5 may be a threshold level to open/close putative OH- (or H+) channels of the D-region.

Carbon Dioxide↗
PubMed1987

Theory of electric dissipative structure in Characean internode.

A band-type alternating pattern of acidic and alkaline regions formed along the Characean cell wall is discussed theoretically. The model system is constructed from linear diffusion equations for the concentration of H+ outside the internode and in the protoplasm. The plasmalemma is taken as a boundary transporting H+ under energy supply by light. The sizes of the protoplasm and extracellular water phase are taken into account explicitly in the present model system to reproduce qualitatively the characteristics observed in various types of experiments. Theoretical analysis shows that the band pattern belongs to dissipative structures emerging far from equilibrium, and is stabilized through the electric current loops produced by locally activated electrogenic H+ pumps and spatially separated passive H+ influx (or OH- efflux) across the membrane. Both the numerical calculation and the theoretical analysis using a generalized time-dependent Ginzburg-Landau equation reveal the following points: (i) the intemodal cell with a larger vacuole in a smaller size of the extracellular water phase tends to exhibit a clearer band pattern; (ii) the increase in viscosity of the external aqueous medium makes the bands appear more easily and, furthermore, distinctly; (iii) the change in size of the extracellular water phase significantly affects the kinetics of the pattern- formation process. These results are interpreted reasonably by taking account of the electric current circulating between the acidic and alkaline regions.

Journal Article↗
PubMed1987

Smoke inhalation injury from newer synthetic building materials--a patient who survived 205 days.

A 25-year-old factory worker sustained inhalation injury and 2 per cent deep burns while fighting a fire in his factory (LSI factory) which was made of new synthetic building materials. He became unconscious and inhaled noxious substances from the smoke. Although he survived the acute stages following injury, his pulmonary function subsequently deteriorated with a damaged trachea and bronchi, repeated attacks of pneumonia, atelectasis, pneumothorax and lung fibrosis, leading to death with hypercapnia (PaCO2 more than 100 mmHg) after 205 days in hospital. Autopsy revealed scarring contraction and dilatation of the trachea and bronchi, acquired bronchiectasis, lobular pneumonia, bleeding, hyperaemia and oedema of the lungs. Systemic administration of corticosteroids was only transiently beneficial in reducing the increased airway resistance.

Adult↗
PubMed1987

PCNA/cyclin: a lupus antigen connected with DNA replication.

Molecular analysis of the proliferating cell nuclear antigen (PCNA) has the 2-fold goal of utilizing the unique tools provided by autoimmune sera to study the function of this important intracellular molecule and to provide insights into the etiology of autoimmune disease. PCNA is expressed in the nucleus immediately preceding S phase and, during S phase is colocalized with sites of active DNA synthesis. There is currently available not only a battery of human sera which can be rendered monospecific for PCNA, but also monoclonal antibodies and rabbit antipeptide antibodies. With these reagents, it might be possible to isolate cDNA clones from cDNA expression libraries.

Antibodies, Monoclonal↗
PubMed1987

Immunohistochemical detection of proliferating cell nuclear antigen in solid human malignancies.

Proliferating cell nuclear antigen (PCNA), also known as cyclin, is a cell cycle-related nuclear protein that is maximally elevated in late G1 and S phases of proliferating cells. In this study, PCNA was identified by paraffin-section immunohistochemistry in 42 of 64 solid human malignancies, and in several benign tissues known to contain proliferating cells. The PCNA-positive nuclei were randomly distributed and ranged from less than 1% (in most cases) to more than 20% of the neoplastic cells. In general, PCNA positivity correlated with mitotic activity and tumor grade. Further study is necessary to evaluate PCNA as a marker of cellular proliferation and a potential prognostic marker in human malignancy.

Histocytochemistry↗
PubMed1987

PCNA (cyclin) autoantibodies and monoclonal antibodies reveal similar patterns of cyclin (PCNA) antigen staining in human cultured cells.

Double immunofluorescence and [3H]thymidine autoradiographic analysis of the same field of transformed human amnion cells (AMA) reacted with proliferating cell nuclear antigen (PCNA) autoantibodies and a monoclonal antibody (mAb 19F4) specific for cyclin (PCNA) revealed similar patterns and sequence of cyclin (PCNA) antigen staining during S-phase. These results suggest that immunofluorescence patterns obtained with PCNA autoantibodies reflect in fact patterns of cyclin (PCNA) antigen staining.

Antibodies, Monoclonal↗