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Biomedical subjects

T Kodama

Publications and source records attributed to T Kodama.

At least 739 records · Page 41Linked to original sources
PubMed1988

Polygonal networks, "geodomes", of adult rat hepatocytes in primary culture.

Polygonal networks, "geodomes", in cultured hepatocytes of adult rats were examined by both light and electron microscopy. On light microscopical examinations of specimens stained with Coomassie blue after the treatment with Triton X-100, the networks were detected 5 days after culture, which consisted of triangles arranged mainly in hexagonal patterns. They surrounded main cell body, looking like a headband, or were occasionally situated over nuclei, looking like a geodesic dome. Scanning electron microscopical observations after Triton treatment revealed that these structures were located underneath surface membrane. Transmission electron microscopical investigations revealed that the connecting fibers of networks consisted of microfilaments which radiated in a compact bundle from electron-dense vertices.

Actin Cytoskeleton↗
PubMed1988

Development of and clinical experience with a new TV monitoring system in electronic endoscopy. Bi-plane TV monitoring system.

We developed a bi-plane TV monitoring system using a TV endoscope (Electronic endoscope manufactured by Toshiba-Machida, Tokyo, Japan) that permits simultaneous display of real-time and prerecorded images. Various findings of the two examinations can be precisely compared using this system, and a detailed evaluation of the progress of peptic ulcers obtained. In addition, the effects of various endoscopic therapies can be accurately evaluated. In endoscopic injection sclerotherapy of esophageal varices, new varices (or recurrent varices) were differentiated. In laser therapy for early gastric cancer, precise delimitation of the lesion for radiation was possible, and the therapeutic effects were more accurately evaluated. These results show the diagnostic as well as therapeutic usefulness of this system. Furthermore, for the examination of the lower digestive tract, X-ray images were incorporated into this system. This is a useful modality for diagnostic and therapeutic procedures in colonic disease.

Electronics, Medical↗
PubMed1988

Purification and characterization of a bovine acetyl low density lipoprotein receptor.

The acetyl low density lipoprotein (LDL) receptor is expressed on macrophages and some endothelial cells and mediates macrophage-foam cell formation in culture. A 220-kDa acetyl LDL binding protein was partially purified from bovine liver membranes and was used to make a specific monoclonal antibody. The 220-kDa protein immunoprecipitated by this antibody retained binding activity, and the antibody was used to detect this protein in cells lining bovine liver sinusoids and on the surface of cultured bovine alveolar macrophages. In the human monocytic cell line THP-1, the expression of both acetyl LDL receptor activity and a 220-kDa acetyl LDL binding protein were dramatically induced in parallel after differentiation to a macrophage-like state induced by phorbol ester. The ligand specificity, tissue and cell-type specificity, and coinduction data indicated that this 220-kDa cell-surface binding protein is probably a receptor that mediates acetyl LDL endocytosis. The 220-kDa protein, which was purified 238,000-fold from bovine lung membranes to near homogeneity using monoclonal antibody affinity chromatography, is a trimer of 77-kDa subunits that contain asparagine-linked carbohydrate chains.

Acetylation↗
PubMed1988

Isolation and characterization of HIV-2 from an AIDS patient in Ghana.

This report describes the isolation and characterization of a retrovirus of the HIV-2 group from a Ghanaian AIDS patient which has different restriction patterns from previously reported HIV-2 viruses. The virus was morphologically very similar to HIV-1 and HIV-2, and had Mg2+-dependent reverse transcriptase. Like previous HIV isolates, it induced severe cytopathic effects in CD4-positive human lymphoid cell lines. Its major proteins were shown to be gp110, p66, p55, p41, gp32, p30 and p26 by Western blot analysis. In dot-blot hybridization experiments, the virus hybridized with a HIV-2 DNA probe, but not with HIV-1 and SIVagm probes in stringent conditions. These data indicate that this Ghanaian virus is a HIV-2 group virus. However, in a Southern blot hybridization experiment, the restriction patterns of this virus, designated HIV-2 [GH-1], were quite different from those of previously reported HIV-2 viruses from West Africa isolated at the Pasteur Institute.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Effect of a rice-rich diet on the therapeutic efficacy of cyclophosphamide with special reference to the enhancement of transplantation immunity.

The present study investigated the problem of whether the therapeutic efficacy of cyclophosphamide in the in vivo Ehrlich ascites tumor system can be improved by adjuvant use of hydrocortisone or of dietary hydrocortisone mobilizers. In the chemotherapy experiment, female ICR mice each received an inoculum of 1 x 10(6) cells of Ehrlich ascites tumor ip followed by 2 ip injections of cyclophosphamide 36 and 37 hr later (2.4 mg/mouse for the 1st injection, and 1.0 mg/mouse for the 2nd injection). The effects of both cyclophosphamide and adjuvant treatments were assessed in terms of either survival rate or cure rate in the 1-month experiment. The results obtained were as follows. 1) Prolonged use of hydrocortisone as an adjuvant can improve the survival of cyclophosphamide-treated mice. 2) Adjuvant use of a rice-rich diet for maintenance increased the rates of both survival and cure in the cyclophosphamide-treated mice. 3) The same maintenance of mice on a rice-rich diet increased transplantation immunity on the one hand, and induced a set of steroidal changes including hydrocortisone excess on the other hand. 4) Evidence is presented to indicate that the beneficial influence of a rice-rich diet on the drug effect is related to an increase of transplantation immunity in the host, and that there could be a causal relationship between hormonal and immunological changes in rice-saturated mice.

Animals↗
PubMed1988

Kinetic study of a change in intracellular ATP level associated with aerobic catabolism of ethanol by Streptococcus mutans.

Streptococcus mutans, a group of lactic acid bacteria and a normal inhabitant of the human oral cavity, generates ATP by substrate-level phosphorylation coupled to oxidation of ethanol (an end product of fermentation of sugars) into acetate in the presence of oxygen (K. Fukui, K. Kato, Kodama, H. Ohta, T. Shima moto, and T. Shimono, Proc. Jpn. Acad. 64B:13-16, 1988). Kinetic measurements were made of the cellular responses of S. mutans FA-1 to ethanol in comparison with those to glucose. In contrast to oxygen-independent acid production from glucose, oxygen was absolutely required for acid production from ethanol. Ethanol elicited a marked increase in the intracellular ATP concentration (ATPi) from a starved level to a steady level which was held constant as long as oxygen was present in the medium. Once oxygen was exhausted, ATPi returned to the starved level without delay. On the contrary, ATPi changes induced by glucose, which were independent of oxygen, followed a rather complicated time course before a steady level was established. Both the steady ATPi and the rate of accompanying oxygen consumption were functions of the ethanol concentration. These two parameters were linearly correlated, indicating that the unimolecular ATP turnover rate, which is independent of the rate of ATP generation in the steady state, can be calculated for cells energized by ethanol. The estimated turnover rate was 1.5 s-1 at 37 degrees C, which is comparable to that for other bacteria energized by glucose under nongrowing conditions.

Adenosine Triphosphate↗
PubMed1988

Isolation and characterization of simian immunodeficiency virus from mandrills in Africa and its relationship to other human and simian immunodeficiency viruses.

Two isolates of simian retrovirus related to the human immunodeficiency virus (HIV) were obtained from apparently healthy mandrills, Papio (Mandrillus) sphinx, in western equatorial Africa. This virus, designated SIVMND (simian immunodeficiency virus from mandrills), appeared morphologically similar to HIV by electron microscopy, showed Mg2+-dependent reverse transcriptase activity, and induced cytopathic effect in human CD4-positive cells. Western blotting (immunoblotting) analyses revealed that the gag and pol products of SIVMND showed cross-reactivity with those of known HIVs and SIVs. Molecular clones covering full-length viral DNA were obtained from closed circular extrachromosomal DNA of SIVMND-infected cells. By clone-on-clone hybridization with known retroviruses of the HIV and SIV groups, SIVMND showed similar cross-hybridization with HIV-1, HIV-2, SIVAGM (African green monkey-derived SIV), and SIVMAC (rhesus macaque-derived SIV) in the gag and pol regions only at low stringency but not at high stringency, a result indicating that SIVMND is a new member of the HIV-SIV group. The existence of distinct SIVs in different monkey species suggest that recent interspecies transfer of HIV-SIV is unlikely in nature.

Animals↗
PubMed1988

Production and characterization of monoclonal antibodies specific for the transmembrane protein of simian immunodeficiency virus from the African green monkey.

Mouse monoclonal antibodies were produced against simian immunodeficiency virus (SIV) from the African green monkey (SIVAGM). The antibodies reacted with the transmembrane protein of all five SIVAGM isolates but not with those of SIVs from the rhesus macaque and mandrill or of human immunodeficiency virus type 1 or type 2, indicating that they recognize a species-specific epitope strongly conserved in SIVAGM. The transmembrane proteins of several SIVAGM isolates were found to vary in molecular size, even in the deglycosylated form after N-glycanase treatment, indicating heterogeneity of the SIVAGM isolates.

Animals↗
PubMed1988

Fluctuations in spontaneous discharge of hippocampal theta cells during sleep-waking states and PCPA-induced insomnia.

1. The spontaneous activity of hippocampal theta cells in head-restrained cats was recorded during slow-wave sleep (SWS), paradoxical sleep (PS), and the attentive state of bird watching (BW). We also recorded theta cell activity during a state of insomnia with pontogeniculoocipital (PGO) waves, which was induced by the administration of p-chlorophenylalanine (PCPA), a selective inhibitor of serotonin synthesis. 2. The time-dependent structure of fluctuations in theta cell activity was evaluated by power spectral analysis and Markovian analysis. The coefficient of variation for these time series was used as a measure of the variability of theta cell activity, which indicates the relative amplitude of fluctuations. 3. During SWS, theta cell activity showed a larger variability and a flat spectrum, i.e., low Markovian properties. During PS, this activity exhibited smaller variability and high spectral density in a low-frequency band (0.01-1.0 Hz), i.e., high Markovian properties. During BW, variability, spectral and Markovian properties were intermediate. 4. The firing pattern of theta cells during PCPA-induced insomnia was similar to that during PS. However, after the administration of either a serotonin agonist, 5-Methoxy-N,N-dimethyltryptamine, or a choline antagonist, atropine sulfate, theta cell activity no longer exhibited PS-like fluctuations, revealing instead a firing pattern similar to that during SWS. 5. During PS and PCPA-induced insomnia, not only the unit activity of theta cells, but PGO activity and theta wave frequency exhibited slow fluctuations, i.e., the high spectral density in the low-frequency band (0.01-1.0 Hz). 6. Cross-correlation analyses were performed between the fluctuations in theta cell activity, theta wave frequency, and PGO activity. These fluctuations correlated with each other during both PS and PCPA-induced insomnia. Bursts of PGO waves especially contributed to these cross-correlations. 7. These results suggest, first, that the slow fluctuations of the theta cell activity during PS and PCPA-induced insomnia is the physiological expression of the removal of aminergic influences and, secondly, that they are dependent on cholinergic mechanisms, including PGO generators.

Action Potentials↗
PubMed1988

Partial purification of androgen receptor from hypertrophic human prostate.

For purification of androgen receptor from hypertrophic human prostate, solutions used for elution of androgen receptor from DNA Sepharose, affinity labeling of the receptor and ability of affinity gel to retain the receptor were examined. Elution with 20 mM pyridoxal 5'-phosphate of the receptor from DNA Sepharose was more efficient than that with diluted pyridoxal 5'-phosphate, high ionic solution or various concentrations of Mg++, 3H-dihydrotestosterone bromoacetate was applicable to covalent binding with partially purified androgen receptor regardless of the low specificity of the ligand. Affinity gel of thiopropyl-Sepharose 6B coupled to 17 alpha-(2', 3'-epoxy-propyl)-5 alpha-dihydrotestosterone was better than Affigel 102 coupled to N-[3-(3-oxo-5 alpha-androstane-17 beta-yloxycarbonyl) propionyloxy] succimide or aminoethyl-Sepharose 4B coupled to 17 alpha-carboxyethynyl testosterone with respect to the rate of retention of androgen receptor. In view of these observations, the following purification procedures were constructed: Removal of DNA Sepharose-binders from the cytosol, 40% ammonium sulfate precipitation, affinity chromatography using thiopropyl-Sepharose 6B coupled to 17 alpha-(2',3'-epoxypropyl)-5 alpha-dihydrotestosterone, and DNA Sepharose chromatography. After affinity labeling of the receptor thus obtained, the molecular weight was estimated. Some 1300-fold purification with a yield of 0.25% of the androgen receptor was achieved. The molecular weight of the receptor was mainly 45 K with 90 K in a lesser amount. The Stokes radius was calculated as 30 A.

Chromatography, Affinity↗
PubMed1988

Characteristics of progestin binder in hypertrophic human prostate.

The human prostate contains a protein which binds with progesterone in a high affinity and low capacity fashion. Characteristics of the progestin-binding protein in the prostate have been disputable; whether it is progesterone receptor or not. Therefore, the characteristics of the progestin binder in the benign hypertrophic human prostate was examined in the present study. After photoaffinity labeling with 3H-R 5020, the binder in the prostate migrated to the site of 42K on polyacrylamide gel electrophoresis under denaturing conditions, and the mobility was apparently different from that of the progesterone receptor in the human uterine endometrium. There was no protein in the prostate immunoreacted with a monoclonal antibody raised against the human progesterone receptor. It was concluded that the progestin-binding protein in the human prostate was different from the progesterone receptor observed in the female human organs.

Blotting, Western↗
PubMed1988

[Recently experienced ten cases of insulinoma--preoperative diagnosis of localization and intraoperative simultaneous monitoring of glucose and insulin].

We have experienced 10 cases of insulinoma during the last 10 years from 1977 to 1986. All cases had strong hypoglycemic symptoms such as disturbance of consciousness, and insulinoma still tended to be misdiagnosed as epilepsy. The diagnosis of insulinoma was easily available from serum IRI (immunoreactive insulin)/plasma glucose ratio in all of the ten cases. As preoperative procedures for the diagnosis of localization, arteriography, computed tomography and portal blood sampling were positive in 6 of 8, 4 of 6 and 2 of 2 patients, respectively. At operation, all insulinomas could be identified by digital palpation. We performed simple excision of the tumor in 6 patients and distal pancreatectomy in 4 patients. The tumors were solitary and benign in all patients, ranging in size from 1.0 cm to 4.5 cm. Three cases were presented as case reports. In these cases, portal blood sampling and/or intraoperative monitoring of plasma glucose and serum IRI were performed. Portal blood sampling was effective even for a case which was negative in image diagnostic procedures. Furthermore, simultaneous monitoring of plasma glucose and serum IRI by quick radioimmunoassay seemed to be a good guide to the completeness of resection of insulin producing tumors.

Adenoma, Islet Cell↗
PubMed1988

[Pharmacological and clinical studies on lipiodol emulsion for hepatocellular carcinoma].

In an attempt to develop a selective long-acting chemotherapy for hepatocellular carcinoma, lipiodol emulsion (Lp-Em) was prepared using non-ionic surfactant, poloxamer-188. A pharmacokinetic study of Adriamycin (ADM) was carried out according to the paddle method, and concentrations of ADM were measured with spectrophotometer at wave length 475 nm. The half time of ADM levels in Lp-Em were longer than that in lipiodol urografin suspension. Histological findings of chemical hepatocarcinogenic rat after their administration showed Lp-Em, lipiodol and ADM accumulations in hepatocellular carcinoma lesion. Transcatheter arterial embolization with Lp-Em containing 40 mg of ADM was performed in 6 patients with unresectable hepatocellular carcinoma. CT scan after treatments revealed high-density areas in the hepatocellular carcinoma lesion as the deposition of lipiodol. Serum concentrations of ADM were significantly lower in a patient treated with Lp-Em than with lipiodol urografin suspension. In conclusion, Lp-Em is thought to be useful for the treatment of hepatocellular carcinoma.

Animals↗
PubMed1988

Sulfated homopolysaccharides with immunomodulating activities are more potent anti-HTLV-III agents than sulfated heteropolysaccharides.

We reported previously that homopolysaccharides with sulfate groups revealed immunomodulating activities--lymphocyte mitogens. We further investigated the role of homopolysaccharides in a different system--cultivation of Molt-4. clone no.8 with supernatant from human T cell lymphotropic virus type III (HTLV-III)-infected TALL-1, utilizing cytopathic effects (CPE), fluorescence antibody technique (FAT), reverse transcriptase (RT) assay and cell proliferation assay. Sulfated homopolysaccharides such as fucoidan, dextran sulfate with three different molecular weights, cellulose sulfate and k-carrageenan showed most potent anti-HTLV-III activities at mitogenic doses. However, neutral homopolysaccharides had no effects on anti-HTLV-III activities Sulfated heteropolysaccharides such a heparin and heparan sulfate had a little effect on anti-HTLV-III activities. It is suggested that sulfate group is most important in inhibiting growth of HTLV-III, but the structure of the polysaccharides is also important, because homopolysaccharides are more potent anti-HTLV-III agents than heteropolysaccharides.

Adjuvants, Immunologic↗