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Biomedical subjects

Y Umezawa

Publications and source records attributed to Y Umezawa.

At least 73 records · Page 4Linked to original sources
PubMed1994

Serum levels of p60 soluble tumor necrosis factor receptor during acute Kawasaki disease.

To evaluate the role of tumor necrosis factor alpha (TNF-alpha) during acute Kawasaki disease, we measured p60 soluble tumor necrosis factor receptor (sT-NF-R) shedding into the circulation in 48 patients with acute Kawasaki disease, all of whom received intravenous infusions of gamma-globulin. Of the 48 patients, 5 had coronary artery lesions. Serum concentrations of p60 sTNF-R and TNF-alpha were measured by a sandwich enzyme immunoassay. Patients with Kawasaki disease had increased serum levels of p60 sTNF-R. We found a positive correlation between serum levels of p60 sTNF-R and levels of TNF alpha during acute Kawasaki disease. Moreover, patients with coronary artery lesions had higher levels of sTNF-R than did those without coronary artery lesions. Our findings indicate that p60 sTNF-R levels in serum may be useful for determining the severity of vascular damage during acute Kawasaki disease, and that patients with Kawasaki disease and high sTNF-R levels seem to be susceptible to coronary artery lesions even if they receive therapy with intravenous infusions of gamma-globulin.

Acute Disease↗
PubMed1994

[Pharmacodynamic study of mitomycin C mixed with fibrin glue for treatment of malignant brain tumors].

The chemotherapy for malignant brain tumors creates two major problems to be solved viz systemic toxicity and interference by the blood brain barrier. The interstitial chemotherapy with sustained release of anticancer drugs has been widely investigated to overcome these problems. The Mitomycin C (MMC) - contained fibrin glue might be a promising candidate for use in local chemotherapy of malignant brain tumors. We investigated pharmacokinetics of the MMC-contained fibrin clot in vitro, activity of the MMC for the cultured glioma cell line, and its effect on the normal mouse brain. The MMC concentration in saline was measured up to 96 hours after the placement of fibrin glue into 5, 10 and 15 ml of saline. Then we periodically replaced the saline to keep the concentration difference of the MMC between the saline and the fibrin clot and evaluated the dissolution of the MMC for 288 hours. The potency of the MMC to suppress the rat glioma cell line was measured after being dissolved from the MMC-contained fibrin clot. The effects of the MMC-contained fibrin clot were histologically evaluated. The MMC-contained fibrin glue, the MMC solution and the fibrin glue were separately injected into the mouse brains. Mice were sacrificed 24, 72, 168 and 336 hours after the injection and brains were examined with photomicroscopy. The MMC was released into the saline rapidly within 24 hours then gradually released until 96 hours had elapsed. Total amounts of the dissolved MMC were proportional to the amounts in the saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

In vivo proton magnetic resonance spectroscopy study on premature aging in adult Down's syndrome.

Proton magnetic resonance spectroscopy (1H-MRS) was performed in a group of 18 adult patients with Down's syndrome (DS) aged 20-46 years, and the peak area ratios (NAA/Cr, Cho/Cr, NAA/Cho) of N-acetylaspartate (NAA), total creatine (Cr), and choline-containing compounds (Cho) calculated separately in the patients in their 20's, 30's, and 40's. In age-matched healthy control groups, there were no significant age-related changes in any of the peak area ratios. In contrast, in the DS group, although the relative amount of NAA (NAA/Cr) showed no significant change with increasing age, the relative amount of Cho (Cho/Cr and NAA/Cho) was significantly increased in the 40's group. At least as judged by MRI, few age-related general morphological changes such as brain atrophy were apparent in the third, fourth, and fifth decade groups. However, the MRI findings considered together with the age-related changes in the peak area ratios suggest that in DS patients in the fifth decade metabolic abnormalities such as degradation and/or rapid synthesis of brain cell membrane may occur prior to neuronal loss and degeneration.

Adult↗
PubMed1993

Human glyoxalase I. cDNA cloning, expression, and sequence similarity to glyoxalase I from Pseudomonas putida.

Glyoxalase I (EC 4.4.1.5) catalyzes the transformation of methylglyoxal and glutathione to S-lactoylglutathione. We have isolated human cDNA clones encoding glyoxalase I from a phorbol myristate acetate-treated U937 cDNA library. This cDNA encodes a protein of 184 amino acids with a calculated M(r) of 20,719. The amino acid composition calculated from the deduced amino acid sequence agreed with that reported for glyoxalase I purified from human erythrocytes. The Escherichia coli cells carrying the expression vector of this cDNA acquired methylglyoxal resistance and the cell lysate showed the high activity of glyoxalase I. The amino acid sequence of human glyoxalase I exhibited 57% identity with Pseudomonas putida glyoxalase I at the C-terminal two-thirds, suggesting that the two enzymes may have originated from a common ancestor.

Amino Acid Sequence↗
PubMed1993

Na+/D-glucose cotransporter based bilayer lipid membrane sensor for D-glucose.

A new type of amperometric blosensor for glucose was fabricated using a Na+/D-glucose cotransporter as the signal-transducing sensory element that exploits the D-glucose-triggered Na+ ion current through bilayer lipid membranes (BLMs). The planar BLM was formed by the folding method across a small aperture of a thin Teflon film. The Na+/D-glucose cotransporter, isolated and purified from small intestinal brush border membrane of guinea pigs, was embedded into BLMs through proteoliposomes. The number of the protein molecules thus incorporated in the present sensing membrane was estimated to be ca. 10(7). The sensor response was measured as an ionic current through the BLM arising from cotransported Na+ ion flux under a constant applied potential and was only induced by D-glucose above 10(-9) M, but not by the other monosaccharides except for D-galactose. The effect of applied potentials, Na+ and K+ ion concentrations, and the addition of a competitive inhibitor, phlorizin, were scrutinized to characterize the sensor output. The results were briefly discussed in terms of the potential use of the Na+/D-glucose cotransporter as a sensory element for D-glucose.

Animals↗
PubMed1993

Therapeutic effect of granulocyte colony-stimulating factor and cephem antibiotics against experimental infections in neutropenic mice induced by cyclophosphamide.

Effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) against severe infections in cyclophosphamide (CY)-induced neutropenic mice were investigated by its single use or by its combination with cephem antibiotics. Treatment with rhG-CSF increased the number of peripheral blood leucocytes and strikingly shortened the duration of the neutropenic state. Most of the regained population in the peripheral blood leucocytes were neutrophils. Functions of neutrophils, such as phagocytic activity, superoxide release, and expression of Mac-1 molecules, were remarkably enhanced by administration of rhG-CSF. When rhG-CSF was administered to CY-induced neutropenic mice before infection, protective effects against various kinds of bacteria were remarkable. On the other hand, such remarkable effects were not observed when rhG-CSF was administered after infections. However, even in the case of post-infectious treatment, a combination therapy of rhG-CSF with cephem antibiotics, particularly with Cefodizime (CDZM), showed a significant improvement in the survival rate and a decrease in the number of viable bacteria in the liver. These results suggest that a combination therapy of rhG-CSF with cephem antibiotics, especially with CDZM, is an efficient regime against severe infections in patients with neutropenia induced by a heavy anti-tumour chemotherapy.

Animals↗
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↗