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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 1,261 records · Page 70Linked to original sources
PubMed1985

Synthetic analogs of the active site of cytochrome P-450cam characterization of thiolpeptide fragment-hemin complexes by optical and ESR spectrometries.

Thiol-containing penta (Leu-Ala-Cys-Ser-Leu) and nona (Leu-Ala-Cys-Ser-Leu-Ile-Glu-Ser-Leu) peptides corresponding to residues 132-136 and 132-140, respectively, of apo-P450 from Psuedomonas putida were synthesized to examine heme-binding by the enzymes in the oxidized (ferric) form. The peptide-hemin complexes prepared in solution were characterized by their optical and ESR spectra. In these complexes without nitrogenous ligands, no ferric complexes in the low-spin state were observed, suggesting that simultaneous axial coordination of Cys-134 (thiolate) and Ser-139 (hydroxyl) of apo-P450cam to the heme is unlikely to occur. In the presence of nitrogenous ligands, such as py, Im and MeIm, the resulting complexes were good models of apo-P450cam-nitrogenous ligand adducts in the low-spin ferric state retaining a thiolate-Fe(III)-nitrogen axial coordination mode, as judged by their spectral pattern as well as by crystal field analysis of ESR g-values.

Amino Acid Sequence↗
PubMed1985

A temperature-sensitive Chinese hamster ovary cell mutant pleiotropically defective in protein export.

We have developed a new selection procedure for mammalian cell mutants defective in protein export by the use of diphtheria toxin, and devised a new screening method for defective protein secretion using nitrocellulose membranes. By the combination of these procedures, we have isolated a temperature-sensitive mutant clone of Chinese hamster ovary cells which shows a pleiotropic defect in protein export. This mutant, designated DS28-6, is temperature-sensitive for growth. Secretion of a series of proteins is markedly inhibited at the non-permissive temperature. These proteins seem to be normally synthesized and accumulated within the cell at the non-permissive temperature and secreted upon shift down to the permissive temperature. When this mutant is infected with vesicular stomatitis virus, oligosaccharide processing of G-protein is arrested at an endoglycosidase-H-sensitive stage at the non-permissive temperature. The lesion of this mutant appears to be in the endoplasmic reticulum or the cis Golgi or both.

Animals↗
PubMed1985

Alteration in the characters of CDP-choline synthetase and phospholipid-choline exchange enzyme upon choline starvation in Chinese hamster ovary cells.

When CHO-K1 cells are cultivated under choline-deficient conditions, the specific activity of CDP-choline synthetase increases and conversely phospholipid-choline exchange enzyme activity decreases, whereas the other three known enzyme activities related to synthesis of phosphatidylcholine remain unchanged. The changes of the former two enzyme activities take place immediately after removal of choline from the medium. The altered activities readily revert to the control levels upon resupplementation of choline to the starved cell culture. The changes upon choline starvation are sensitive to cycloheximide, while the restoration processes are insensitive to the drug. The activity of CDP-choline synthetase in unstarved control cells is found in both the soluble and membrane fractions. The Km value of the enzyme in the soluble fraction for choline phosphate differs from that in the membrane fraction. Asolectin alters the Km value of the former to a value close to that of the latter and raises its Vmax value, whereas it hardly affects the Km and Vmax values of the latter. In choline-starved cells, the activity is exclusively found in the membrane fraction. The change in the subcellular distribution of the activity upon choline starvation is sensitive to cycloheximide. The altered subcellular distribution reverts to the initial status upon resupplementation of choline even in the presence of cycloheximide. The activity of the phospholipid-choline exchange enzyme is exclusively found in the membrane fraction for both starved and control cells. The properties of the enzyme are altered upon choline starvation with respect to the Vmax value for choline and the Km and Vmax values for Ca2+. These altered kinetic parameters are changed by egg yolk phosphatidylcholine so as to be indistinguishable from those in unstarved control cells. We discuss the mechanism of the alterations in the characters of both enzymes in response to choline starvation.

Animals↗
PubMed1985

Rat lymphoid cell lines producing human T cell leukemia virus. II. Constitutive expression of rat interleukin 2 receptor.

Three rat lymphoid cell lines (TARS-1, TARL-2, and TART-1) (12) transformed by human T cell leukemia/lymphoma virus I (HTLV-I) had rearrangement of the beta chain gene of the T cell antigen receptor, and had integrated proviral DNA from HTLV-I in their genomes. As is the case with adult T cell leukemia (ATL)-derived human T cell lines transformed by HTLV-I, these rat cell lines unequivocally expressed interleukin 2 (IL-2) receptor, as determined by radiolabeled IL-2 binding. By Scatchard plot analysis, one of the cell lines, TART-1, proved to have high affinity receptors (Ka = 1.3 X 10(11)/M and 8.8 X 10(9)/M). Rat IL-2 receptor, not human IL-2 receptor, was expressed on HTLV+ rat cell lines, as demonstrated by the fact that they expressed antigens reactive with monoclonal antibodies (ART-18) against rat IL-2 receptor, but not with anti-Tac antibodies. The collective evidence indicates that the endogenous IL-2 receptor gene is activated in human and rat lymphoid cell lines with HTLV-I production. The mechanism of abnormal IL-2 receptor expression in HTLV infection is discussed.

Animals↗
PubMed1985

The synaptic relationship between vasoactive intestinal polypeptide (VIP)-like immunoreactive neurons and their axon terminals in the rat small intestine: light and electron microscopic study.

The present study demonstrates synaptic contacts between vasoactive intestinal polypeptide (VIP)-like immunoreactive neurons and immunoreactive axon terminals in the submucous and myenteric plexuses of the rat small intestine. Our observations suggest that VIP afferents directly affect the VIP neurons in the small intestine via synapses.

Animals↗
PubMed1985

Registry and follow-up systems of trophoblastic disease in Japan.

With recent progress in chemotherapy, the prognosis of patients with trophoblastic disease has greatly improved, but the remission rate of patients with choriocarcinoma remains unfavorable. To improve the prognosis of these patients, early detection and early treatment are essential. Under the leadership of the Committee of Trophoblastic Disease of the Japan Society of Obstetrics and Gynecology, regional registries of trophoblastic disease were started in 1974. By 1982 14 prefectures with a total population of 46,893,620 were included in the registry. The early detection and treatment and follow-up made possible by the registry in addition to the introduction of advanced chemotherapy may be responsible for a rapidly decreasing trend in the death rate from this disease.

Choriocarcinoma↗
PubMed1985

Dystrophic axons in the nucleus gracilis of the normal rat containing cholecystokinin-like immunoreactivity. Light- and electron-microscopic observations.

Cholecystokinin immunoreactive (CCKI) axons in the nucleus gracilis of the normal rat were studied by light and electron microscopy using the peroxidase-antiperoxidase (PAP) immunocytochemical method. Immunoreactivity was found in both normal and dystrophic axons at various ages. Slightly enlarged CCKI varicosities were first observed in 2-month-old rats, gradually increased in number (max. at 21 months) and in diameter (up to 20 micron at 21 months), and then decreased (at 27 and 36 months). Dilatated CCKI fibers continuous with dystrophic varicosities also tended to increase proportionally in diameter. The dystrophic CCKI axonal profiles, first identified at the light-microscopic level and then observed under electron microscopy, had consistently characteristic features. In addition, numerous dystrophic nonreactive axonal profiles had morphological features differing from those of dystrophic reactive ones at advanced ages. These findings suggest that CCK may be partly involved in the formation of dystrophic axons in the nucleus gracilis.

Aging↗
PubMed1985

Analyses of the specificity of mouse monoclonal antibodies to syngeneic and allogeneic thyroglobulins.

Fourteen mouse monoclonal antibodies (mAbs) to syngeneic and allogeneic thyroglobulins (Tgs) were prepared to study antigenic determinants, their variation among mouse Tgs, and cross-reactivity with various species Tgs. The binding pattern to the Tg panel classified mAbs into three groups but the clustering by competitive-binding inhibition with unlabeled mAbs suggested that at least five antigenic regions existed on the Tg molecule. Mouse Tgs showed no antigenic variation to our mAbs. The cross-reaction with other species Tgs was strictly limited to rat Tgs, excluding one mAb (8.1.1) which reacted with rat and human Tgs. The competitive-binding inhibition by various doses of Tgs substantiated the binding pattern to the Tg panel and furthermore demonstrated that both complete and partial cross-reactions existed.

Animals↗
PubMed1985

Epitopic difference among rat thyroglobulins.

Epitopes on thyroglobulin (Tg) were examined using mouse monoclonal antibodies (mAbs). Two out of 6 mAbs indicated a remarkable difference in binding to three rat Tgs. Namely, they bound to one Tg as well as immunized Tg but could not bind to another at all. They could hardly bind to the third Tg. Another mAb was similar, to some extent, in binding to three rat Tgs as described above, although three other mAbs bound almost equally to three rat Tgs. Since competitive binding inhibition by Tgs supported the result of the binding study, the epitopic difference on rat Tgs was confirmed. Furthermore, competitive binding inhibition by unlabeled mAbs revealed that six mAbs recognized different epitopes individually. Therefore, there were at least two unique epitopes located on one rat Tg but not located on another. The relation between unique epitopes and thyroiditis in the rats used in the present study is also discussed.

Animals↗
PubMed1985

Camptodactyly caused by an abnormal lumbrical muscle.

A thirteen-year-old girl, who complained of pain in the palm and difficulty in extension of the right little finger, had an abnormal insertion of the lumbrical muscle into the flexor digitorum superficialis tendon. The symptoms were relieved by detaching the lumbrical muscle and transferring its tendon into the lateral band.

Adolescent↗
PubMed1985

Fluorescence enzyme immunoassay of 21-deoxycortisol in plasma and dried blood sample on filter paper.

An enzyme immunoassay of 21-deoxycortisol (21-DOF) in plasma and dried blood spotted on filter paper has been developed. 21-DOF was conjugated to horseradish peroxidase by the mixed anhydride method. Separation of free and bound fractions was done by the use of insolubilized antibody, prepared by coating polyacetal beads with purified IgG of goat anti-rabbit IgG serum. The enzyme activity was measured by the fluorophotometric method using 3-(p-hydroxyphenyl) propionic acid and H2O2 as substrates. The sensitivity of the present method was 0.5 pg/tube for 21-DOF. The intra- and interassay coefficients of variation were 3.2 and 8.2, and 7.9 and 9.2% respectively. The present enzyme immunoassay could be applied to mass-screening for congenital adrenal hyperplasia.

17-Hydroxycorticosteroids↗
PubMed1985

Distal transposition of rat caecum does not render it susceptible to carcinogenesis.

As the relative resistance of rat caecum to chemical carcinogens could reflect its luminal environment, caecal mucosa was exposed to the distal faecal stream in male Sprague-Dawley rats (n = 50) previously treated with azoxymethane (total dose 90 mg/kg sc). After colonic transection at the pelvic brim, the caecum was inserted isoperistaltically between colocaecal and caecorectal anastomoses (n = 30); an ileocolic anastomosis restored intestinal continuity. Controls (n = 20) had transection and reanastomosis at equivalent points of the bowel, plus caecotomy and resuture. Caecal crypt cell production rate, as determined stathmokinetically at 28 weeks, was not consistently affected by transposition. No tumors developed in either transposed or orthotopic caecum, apart from three suture-line tumours found at the caecotomy site in controls. The colonic tumour yield in controls (1.4 +/- 0.3 per rat : mean +/- SEM) matched that after transposition (1.5 +/- 0.2), but anastomotic tumours were twice as common after transposition (p less than 0.05) and rectal tumours were increased four-fold (p less than 0.05). The caecum remains resistant to carcinogenesis despite transposition to a distal colonic environment. Local epithelial defence mechanisms are more important than luminal contents in maintaining this resistance.

Animals↗
PubMed1985

Interleukin-2 receptor (Tac antigen) expressed on adult T cell leukemia cells.

We studied the expression of the interleukin-2 (IL-2) receptor and the proliferative response to exogenous IL-2 of peripheral blood leukemic cells from patients with adult T cell leukemia (ATL) in order to see whether IL-2 receptor expressed on ATL cells is different from normal IL-2 receptor and whether it plays a role in the neoplastic growth in ATL. Peripheral blood leukemic cells from 42 patients with ATL examined expressed IL-2 receptors that were detected by anti-Tac monoclonal antibody when examined immediately after the separation of cells or after the culture for 24 or 48 h. The number of anti-Tac binding sites ranged from 3,100 to 11,400 in fresh cells and from 3,600 to 96,000/cell in short-term cultured leukemic cells, whereas phytohemagglutinin-P (PHA-P)-stimulated normal T cells exhibited 6,900-35,000 anti-Tac binding sites per cell. ATL-derived and human T cell leukemia/lymphoma virus, type I (HTLV-I)-infected cell lines such as MT-1 and Hut102 expressed a much higher number of anti-Tac binding sites. Leukemic cells from 15 patients with ATL examined showed no or very poor proliferative response to various concentrations of immunoaffinity-purified IL-2, although they expressed Tac antigen (Ag). Radiolabeled IL-2 binding experiments demonstrated that ATL leukemic cells could bind IL-2, and they expressed both high and low affinity IL-2 receptors, although the number of high affinity IL-2 receptor was much less than that of low affinity IL-2 receptor and that of anti-Tac binding sites. In contrast, leukemic T cells from a patient with T cell chronic lymphocytic leukemia (CLL), in whom HTLV-I infection was not demonstrated, responded as well as PHA-P-stimulated normal T cells, and their IL-2 receptors, unlike ATL cells, were modulated (down regulated) by anti-Tac antibody. No differences were noted between ATL cells and normal activated T cells in one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the IL-2 receptor. Thus, leukemic cells in ATL spontaneously and continuously express IL-2 receptor, which appears to be abnormally regulated and unresponsive to IL-2. These results, taken together with those on normal IL-2 receptors on HTLV-I-negative T-CLL cells, suggest that abnormal expression of the IL-2 receptor in ATL is closely associated with HTLV-I infection and may play a role in the neoplastic growth of ATL cells.

Adult↗
PubMed1985

Pathology of spontaneous colibacillosis in a broiler flock.

Forty-eight of 134 chickens collected from a flock on a broiler farm were diagnosed pathologically and microbiologically to have colibacillosis. Both acute septicemia (seven birds, 1 to 36 days old) and subacute serositis (41 birds, 5 to 57 days old) were found. The former consisted of necrosis with fibrinous exudates in the ellipsoids and lymphoid follicles of the spleen, and fibrinous thrombi in sinusoids of the liver with occasional necrosis of hepatic cells. The latter had fibrinopurulent inflammation with granulomatous changes in the serosal tissues--including the epicardium, pericardium, and hepatic peritoneal sac--accompanied by septicemic lesions in the spleen and liver. Respiratory lesions (airsacculitis, pneumonia, and tracheitis) were noted in most chickens affected with acute septicemia and subacute serositis. Degenerative changes also were observed in the bursa of Fabricius.

Acute Disease↗
PubMed1985

Involvement of different receptor subtypes for the production of in vitro and in vivo effects in a series of synthetic enkephalin analogues.

Enkephalin analogues of tyrosyl group on the N-terminal and Phe-ol or phenylethylamine (PHA) group on the C-terminal which are connected with different chain length were tested for their activities in vitro and in vivo. The inhibitory effect of the synthetic peptides on the electrically evoked contractions of isolated longitudinal muscle strips of guinea pig ileum were weaker than that of morphine or Leu-enkephalin and tended to decrease by increasing the number of methylene group,-(CH2)n-, n = 1-5, between N- and C-terminal. Compounds with PHA group on the C-terminal, n = 4 and 5, showed the least activity. The effect of peptides with short chains of methylene groups, n = 1 or 2, and Phe-ol on the C-terminal were antagonized by naloxone but others were insensitive to naloxone. Differing from in vitro activity, compounds with PHA on the C-terminal with a chain of 4 methylene groups produced short lasting analgesia after i.c.v. injection as well as the compounds with Phe-ol on the C-terminal and 1 or 2 methylene groups. The analgesic effect of these compounds were completely antagonized by naloxone. At a high i.c.v. dose, all the synthetic peptides, except the one with PHA on the C-terminal with a chain of 4 methylene group, produced convulsions and/or ipsilateral rotation to the injection side. These behavioral effects were not antagonized by naloxone. Thus, minor alterations in the chemical structure of enkephalin analogues resulted in the changes of their receptor selectivity and potencies in vitro and in vivo.

Analgesia↗