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Biomedical subjects

Y Umezawa

Publications and source records attributed to Y Umezawa.

At least 19 recordsLinked to original sources
PubMed1992

Efficient cDNA cloning method using solid phase DNA probe.

We are now developing a novel and efficient method using solid phase DNA probe to isolate a particular recombinant cDNA from single stranded cDNA library. Target clone coding metapyrocatechase (MPC) and cDNA library constructed from mRNA of U-937 (human lymphoma cell line) were converted to single stranded form by superinfection of helper phage (M13KO7). Probe DNA (25 mer) composed of a portion of the target cDNA was synthesized, attached to an HPLC gel and used as a solid phase DNA probe. Hybridization between probe DNA and target clone was performed in an Eppendorf tube within a few hours. Competent cell (JM109) was transformed with about one-twentieth of hybridized and eluted fraction by Hanahan's method. From the mixture of 1 ng of MPC vector and 5 micrograms of cDNA library, we obtained 50 colonies containing MPC gene out of 63 transformed colonies.

Catechol 2,3-Dioxygenase↗
PubMed1991

Ion channel sensors for glutamic acid.

Coulometric biosensors using glutamate receptor (GluR) ion channel protein as a signal-amplifying sensory element that exploit the glutamate-triggered Na+ ion current through bilayer lipid membranes have been fabricated. The formation of stable planar bilayer lipid membranes was achieved by applying the folding method across a small circular aperture bored through a thin polyimide film. The multichannel type sensing membranes, formed across an aperture of ca. 120 microns diameter, contained more than 10 GluR proteins and showed L-glutamate-triggered response as a composite of individual single-channel currents. The single-channel type sensing membranes, formed across an aperture of ca. 20 microns diameter, contained a sufficiently small number of GluR proteins so that the response was observed as a series of single-channel pulse currents. Dependence of the integrated channel current on the glutamate concentration was examined. A sharp concentration dependence of up to ca. 1.5 x 10(-7) M and 3 x 10(-6) M for the multichannel and single-channel type sensors, respectively, was observed. A high selectivity for L-glutamate compared with D-glutamate for inducing the channel current was observed. A detection limit as low as ca. 3 x 10(-8) M was attained for the multichannel type sensor. This remarkable sensitivity is discussed in terms of the potential use of GluR ion channel protein for a new type of sensing system.

Biosensing Techniques↗
PubMed1991

An ultrasound-guided stereotactic apparatus for intracranial mass lesions.

One of disadvantages of conventional stereotactic operation for intracranial mass lesions is that it is basically a blind procedure even if the operation is performed in a gantry of a CT scan. High resolution ultrasound image gives real-time information on intracranial pathology such as bleeding, remaining cyst fluid or haematoma. The authors report an ultrasound guided stereotactic apparatus which gives real-time images of the lesion during operation.

Biopsy, Needle↗
PubMed1991

Increased expression of Fc epsilon R2/CD23 on peripheral blood B lymphocytes and serum IgE levels in Kawasaki disease.

We analyzed the expression of Fc epsilon R2/CD23 on the peripheral blood B lymphocytes of 10 patients with Kawasaki disease (KD) using a fluorescence-activated cell sorter. The absolute count of CD23-positive B lymphocytes and the ratio of CD23-positive B lymphocytes to B lymphocytes were high during the acute stage of KD in comparison to those during the convalescent stage and in control subjects. In addition, both the increased number of CD23-positive B lymphocytes and the increased serum IgE levels appeared during the latter part of the acute stage. These results suggest that the increased number of CD23-positive B lymphocytes during the latter part of the acute stage in KD reflect the activation of B lymphocytes and have an important role in IgE-mediated immunity.

Antibodies, Monoclonal↗
PubMed1991

Identity of brain-associated small cell lung cancer antigen and the CD56 (NKH-1/Leu-19) leukocyte differentiation antigen and the neural cell adhesion molecule.

Previous studies have demonstrated the monoclonal antibody, TFS-4, to recognize a cell surface antigen, 124,000 Daltons, of molecular weight expressed selectively on small cell lung cancer but not on non-small cell lung cancer, and to cross-react with the human brain, cardiac muscle and some smooth muscle cells. The cross-reactivity of TFS-4 with peripheral blood lymphocytes was examined by two color immunofluorescence analysis, using monoclonal antibodies to leukocyte differentiation antigens. Flow cytometric analysis revealed an identical subset of cells to express both BASCA and CD56(NKH-1 antigen). The immunofluorescence profiles for both TFS-4 and NKH-1 were, furthermore, identical to those of the background controls, identicating identical quantities of the antigens to be present on each cell within the population. Since CD56 has been show to be identical to the neural cell adhesion molecule (N-CAM), we determined the amino-terminal amino acid sequence of BASCA purified from the human brain. The amino-terminal amino acid sequence of BASCA was identical to that of N-CAM.

Amino Acid Sequence↗
PubMed1990

Slit ventricle syndrome after cyst-peritoneal shunting for the treatment of intracranial arachnoid cyst.

Serious complications following installation of a cyst-peritoneal shunt in an 8-year-old boy with asymptomatic arachnoid cyst in the middle cranial fossa are reported. Highly elevated intracranial pressure without association of ventriculomegaly seen in this patient indicates slit ventricle syndrome caused by malfunction of the cyst-peritoneal shunt. This phenomenon is worth recognizing as a possible consequence of cyst-peritoneal shunting for the treatment of intracranial arachnoid cyst.

Arachnoid↗
PubMed1989

Identification and characterization of receptors for granulocyte colony-stimulating factor on human placenta and trophoblastic cells.

Since radioiodination of human granulocyte colony-stimulating factor (G-CSF) is difficult, we synthesized a mutein of human G-CSF that retains full biological activity and receptor-binding capacity for at least 2 weeks after radioiodination. Receptors for human G-CSF were characterized in the plasma membrane fraction from the human term placenta (human placental membranes) and trophoblastic cells by using the 125I-labeled mutein of human G-CSF (KW-2228). The specific binding of 125I-labeled KW-2228 to placental membranes was pH-dependent, with maximal specific binding at pH 7.8; it increased linearly with protein to 3.7 mg of protein per ml and was both time- and temperature-dependent, with maximal binding at 4 degrees C after a 24-hr incubation. When we examined the ability of hematopoietic growth factors to inhibit 125I-labeled KW-2228 binding, we found that KW-2228 and intact human G-CSF inhibited 125I-labeled KW-2228 binding, whereas erythropoietin or granulocyte-macrophage colony-stimulating factor did not. Scatchard analysis revealed a single receptor type with a Bmax of 210 fmol/mg of protein and a Kd of 480 pM. The human G-CSF receptors on human placental membranes were shown to consist of two molecular species of 150 kDa and 120 kDa that could be specifically cross-linked to 125I-labeled KW-2228. Human trophoblastic cells, T3M-3, also possessed a single receptor for G-CSF with a Bmax of 533 receptors per cell and a Kd of 390 pM. Thus we have identified the receptor for human G-CSF on human placental membranes and trophoblastic cells, and the presence of this receptor in these membranes suggests that human G-CSF plays some role in the feto-placental unit during human development.

Binding, Competitive↗
PubMed1989

Altered immune responsiveness in patients with chronic glomerulonephritis.

In order to detect abnormalities in humoral immunity and to determine immunogenetic traits underlying chronic glomerulonephritis, sera from 260 patients who had chronic glomerulonephritis and who were undergoing hemodialysis were tested for naturally occurring antibodies against mycoplasma and 22 different viruses. Among the 23 microorganisms tested, antibody titers were significantly lower against 12, higher against 3, and no different against 8 when compared with titers of 43 normal subjects. The data were analyzed further by plotting each in a 23-dimensional space according to their standardized antibody titers. Multivariate cluster analysis by the Ward's method revealed 3 large clusters differing from each other in natural antibody titers, and one of the clusters included 74% of the normal controls, while two other distinct clusters comprised the majority of the patients. The level of BUN, creatinine, and duration of hemodialysis treatment did not differ significantly among patients in these three different clusters. Our study suggests that patients with chronic glomerulonephritis being treated by hemodialysis have altered levels of naturally occurring antibodies to microorganisms. This alteration is not caused by just the uremic state or hemodialysis but immunogenetic regulation may also play a part.

Adolescent↗
PubMed1989

[Clinical analysis on the temporomandibular joints of the fifteen patients of rheumatoid arthritis].

It is seemed to be really important, when making a selection on the treatment for rheumatoid arthritis, to gain an insight into progress and activity of the disease. This analysis was taken in order to look upon the clinical symptoms and the radiographic abnormalities of the temporomandibular joints, obtained from fifteen rheumatoid arthritis patients who has visited on our department, since 1974. Ten patients (66.7%) had clinical evidences of temporomandibular joint. The most frequent symptom was pain on movement, followed by disturbances on mouth opening and crepitation. Patients who had been suffering from the disease for a long period offered more frequent clinical evidences. The acute phase symptoms, such as disturbances on mouth opening, swelling and oppressive pain in the preauricular area, was found in one patients. All of the patients showed some radiographic abnormalities. We've devised a criteria on the degree of condylar absorption on the purpose of comparison to the other abnormalities. The degree 1 was found in 3 joints, the degree 2 in 12 joints, the degree 3 in 14 joints, and the degree 4 in 7 joints. An absorption on the articular fossae and the tubercles were well along with this degrees. The higher degree the more frequent of clinical evidences in each joints was disclosed. And the period of the disease was related on the degrees, too. We can expect the bone scintigraphy by using 99mTc-MDP to be a good way for expression of the activity of the disease.

Arthritis, Rheumatoid↗
PubMed1989

[A new apparatus using the Micro Ultra-Sonic Aspirator (MUSA) system for microneurosurgery].

Matsumoto was the first to present the NIIC UltraSonic Aspirator for CT guided stereotactic aspiration of intracerebral hematoma. Based on the NIIC Aspirator, the authors have developed a useful tool for microsurgery by adapting conventional ultrasonic aspirators. This was done by making the aspirator lighter and more handy for use during microsurgical procedures. A newly devised apparatus using the Micro Ultra-Sonic Aspirator (MUSA) was applied clinically to surgical treatment for brain tumors, arterio-venous malformations (AVMs) and intracerebral hematomas. Using the MUSA system, it became easier to remove successfully tumorous mass and the nidus of AVM, because it minimized the risk of injury to the normal structures such as the surrounding brain tissue, vascular systems and the cranial nerves.

Brain Diseases↗
PubMed1988

Inhibition of DNA synthesis by alpha-1-antichymotrypsin.

The effect of alpha-1-antichymotrypsin (ACT), which is known as an efficient serum protease inhibitor and is detected in tumor cell nuclei, on DNA synthesis was studied. ACT inhibited the activity of DNA polymerase alpha purified from human stomach adenocarcinoma. Other human serum proteins including serum albumin, alpha-1-acidglycoprotein, alpha-1-antitrypsin, and immunoglobulin G, as well as other protease inhibitors, such as leupeptin, pepstatin, PMSF and chymostatin, did not affect the activity of DNA polymerase alpha. It was therefore concluded that the inhibitory action of ACT on DNA polymerase alpha was direct phenomenon unrelated to its protease inhibitory activity. Furthermore, the effect of ACT on DNA synthesis was also studied using lysolecithin-permeabilized cultured human stomach carcinoma cells. ACT added in the medium inhibited DNA synthesis and the degree of inhibition depended on incubation time. It was proportional to ACT concentration and the concentration of ACT required for 50% inhibition was 0.8 mg/ml.

Adenocarcinoma↗