Biomedical subjects
Publications and source records attributed to M Tada.
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Although a sliding tube made of plastics is very effective to keep the sigmoid colon in a straight position, there is some difficulty in handling the colonoscope, being restricted by the length of the scope. For the purpose of covering the demerits of the conventional sliding tube, a new slit sliding tube which is made up of three parts was devised by us. After straightening the sigmoidal loop, the three parts of the apparatus are joined together. Then the slit sliding tube is inserted into the descending colon with safety and ease. By using the slit sliding tube, handling of the colonoscope is scarcely restricted and becomes easy. Moreover, the slit sliding tube can be used even for the shorter scopes, by which the distal parts of the colon can be more easily examined in comparison with conventional techniques.
We have developed a simple method which can recover the highly purified macrophages or monocytes in suspension from mouse peritoneal exudate cells and human perpheral blood mononuclear cells. Plastic Petri dishes coated overnight with heat-inactivated fetal calf serum (FCS) selectively bind macrophages and monocytes. The adherent macrophages and monocytes are easily removed by incubation in phosphate-buffered saline containing 0.2% ethylenediamine tetraacetate (EDTA) and 5% FCS, and recovered as a cell suspension with greater than 95% purity. A small number of isolated cells can restore the mitogenic response to phytohemagglutinin (PHA-P) of macrophages-depleted lymphocytes and can lyse 51Cr-labeled target cells in an antibody-dependent cell-mediated cytotoxicity system. Thus, the method should be valuable for studies of various functions of macrophages and monocytes from different immune tissues of man and animals.
We evaluated the usefulness and limitations of praecordial ST segment mapping as a clinical means of assessing the size of acute myocardial infarction in 14 patients with anterior myocardial infarction and 13 patients with inferior myocardial infarction. sigma ST, the sum of ST segment elevations, and nST, the number of leads showing ST segment elevation, were obtained from serial electrocardiograms recorded through 39 praecordial leads. The infarct size and period of the evolution of myocardial infarction were estimated respectively from the total creatine kinase (CK) released and the serial changes of the CK releasing rate. sigma ST and nST obtained at the time when the CK release had ceased correlated closely with the total CK released. Peak sigma ST and nST, and values 48 hours after the onset of myocardial infarction, also correlated well with the total CK released; but those on admission or 12 hours after the onset correlated poorly. These results suggest that sigma ST and nST at the end of evolution of myocardial infarction or 48 hours after the onset may be two useful indices for the assessment of infarct size in patients with either anterior or inferior myocardial infarction.
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Thirty cases of ulcerative colitis were examined endoscopically by means of magnifying colonoscope with dye spraying method (the combined method), and their minute mucosal structures were classified into four categories endoscopically, which correlated well with the histological findings. By this procedure, it was easy to detect the subsidence of inflammation of the mucosa in the quiescent phase or to reveal the active inflammatory involvement of the bowel. Moreover, inspecting the minute changes of the colonic mucosa detected by the combined method, remission was more correctly decided and rigid control is contributing to the decrease in the recent rate of recurrence of ulcerative colitis.
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A rounding cell-forming--GC strain, which is a variant of a syncytial giant cell-forming herpes simplex virus (+GC Miyama strain), was highly attenuated for Swiss, BALB/c nu/nu, and nu/+ mice, whereas +GC was highly virulent to all the mice tested. +GC and -GC were antigenically indistinguishable from each other by cross-neutralization and cross-immunization. Immunosuppression induced by cyclophosphamide converted the nonlethal -GC infection of mice into a fatal infection. -GC replication in tissue culture was more effectively suppressed by spleen cells immunized with either +GC or -GC than was the +GC replication. -GC replication was also inhibited more effectively by antibody or the antibody-dependent cell-mediated system than was the +GC replication. -GC is highly sensitive to mouse interferon, but +GC was relatively resistant. These findings indicate that attenuation of this avirulent -GC strain may be due to a high susceptibility of its replication to humoral and cell-mediated defense factors. The probable roles of each defense factor in recovery from the infection with virulent and attenuated herpes simplex virus are also discussed.
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4-Nitrosoquinoline 1-oxide induced malignant tumors at the subcutaneous site of injection in mice. It affected Escherichia coli to induce the so-called UV-type lesion in cellular DNA. DNA base-quinoline adducts produced by the treatment of mammalian cellular DNA with this carcinogen were proved to be identical with those obtained by the action of 4-nitroquinoline 1-oxide. Although this carcinogen was reactive enough to modify DNA chemically by itself, a different DNA modification took place in a chemical process from thos obtained in the in vivo process.
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Synthetic and natural DNAs we;e reacted with 4-hydroxyaminoquinoline 1-oxide (4-HAQO) in an in vitro enzyme system. The amount of 4-HAQO bound to DNA varied significantly depending on the DNA used. The base sequence as well as the base composition affected the binding. Optical melting profiles of 4-HAQO-modified DNAs were examined. Decrease in the melting temperature and broadening of the transition width were commonly observed. Melting fine structure of lambda-phage DNA became less clear according to the modification. The shape of the melting curves of synthetic polynucleotides was little affected by binding, which suggests that the binding sites are distributed randomly along a DNA molecule. Binding of 4-HAQO to a purine base may distort the secondary structure of neighboring base pairs in a DNA molecule. Degree of the distortion can be estimated as a free energy increment associated with the binding. It was found that the free energy increment differs considerably among the polynucleotides with different base sequences.
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