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Biomedical subjects

T Takami

Publications and source records attributed to T Takami.

At least 91 records · Page 5Linked to original sources
PubMed1989

Nucleolar organizer regions in hepatocarcinogenesis induced by N-2-fluorenylacetamide in rats: comparison with bromodeoxyuridine immunohistochemistry.

The number of silver-stained nucleolar proteins (AgNOR) was counted in preneoplastic and neoplastic rat liver lesions induced by N-2-fluorenylacetamide (FAA) and was compared with that of bromodeoxyuridine (BrdU)-incorporating cells detected immunohistochemically using monoclonal antibody against BrdU. Male ACI/N rats were given diet containing 200 ppm FAA for 12, 16 or 20 weeks to induce hepatocellular foci and tumors. The mean numbers of AgNOR stained by a one-step silver colloid method and BrdU-labeling indices in various liver cell lesions were as follows: nontreated liver (n = 20), 1.20 and 0.08; nonlesional areas (n = 20), 1.33 and 0.13; altered liver cell foci (n = 80), 2.04 and 4.05 [eosinophilic cell type (n = 20), 1.78 and 1.82; clear cell type (n = 20), 1.45 and 1.77; basophilic cell type (n = 20), 1.99 and 4.58; hyperbasophilic cell type (n = 20), 2.94 and 8.02]; neoplastic nodules (n = 10), 3.11 and 2.99; hepatocellular carcinomas (n = 10), 7.22 and 8.29. Thus, the mean number of AgNOR and the value of BrdU-labeling index were well correlated and both values showed a stepwise increase from normal liver cells to liver cell carcinoma, although some scatter was present. These data suggest that mean number of AgNOR may reflect the cellular kinetics in rat hepatocarcinogenesis, and the one-step silver colloid method for demonstration of AgNOR may therefore be a simple and useful staining to examine the proliferative nature of cells.

2-Acetylaminofluorene↗
PubMed1989

Involution of lymph node histiocytes in AIDS.

Lymph nodes of human immunodeficiency virus (HIV)-infected patients were studied histologically and immunohistochemically to elucidate the pattern of involution of various histiocytes in AIDS. Specimens consisted of one node with hyperplasia, five with atrophy, and three with severe atrophy. Antibodies such as L25, ID1, My4, 12, anti-Leu 3a, KiM4, OKT6 and anti-S100 protein were used for identification of the histocytes. Another antibody, VAK5, was used to demonstrate HIV antigen. T-zone histiocytes were mildly decreased in the hyperplastic node, but considerably decreased in the atrophic nodes. My4+ sinus histiocytes were unchanged in number and enlarged in the hyperplastic node, but not decreased in the atrophic nodes. Follicular dendritic cells (FDCs), defined by KiM4, were mostly depleted in the atrophic nodes. The T4 antigen was detected in some of the sinus histiocytes of the atrophic nodes. T6-positive cells were not found in any of the nodes. HIV antigen was detected only in FDCs. It is therefore suggested that various histiocytes respond differently to HIV, and that T-zone histiocytes and sinus histiocytes persist up to the late stage of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Effects of supplementation with branched-chain amino acids on protein-nutritional status in rats treated by carbon tetrachloride].

A study was conducted to investigate effects of oral supplementation with branched-chain amino acids (BCAA) on protein-nutritional status in rats with liver cirrhosis. Liver cirrhosis was induced in male strain Sprague-Dawley rats by simultaneously administrating carbon tetrachloride (500 mg/kg, twice a week, intracutaneously) and phenobarbital (0.05% in drinking water, ad libitum) for 30 weeks. Following treatment with carbon tetrachloride and phenobarbital, cirrhotic rats received oral supplementation of BCAA with varying ratio among isoleucine (Ile), leucine (Leu) and valine (Val), or with varying content of total BCAA in the diet (Final content of total nitrogen was kept consistent by addition of glutamine). Nutritional efficacies of diets as described above were evaluated employing those protein-nutritional parameters as nitrogen balance and plasma levels of total protein, albumin and free neutral amino acids. Following results were obtained: 1. Compositional ratio of Ile:Leu:Val at 1:2:1.2 or at 2:1:1 was found to be more effective on diets which contained ILe:Leu:Val at 1:1:2 or either Val, Ile or Leu alone. 2. As to content of total BCAA in the diet (0, 2.5, 5, 10%), supplementation level of 2.5% was found to be most appropriate in terms of effects on nitrogen balance and on plasma protein concentration. In conclusion, 2.5% BCAA in the diet with the ratio of Ile:Leu:Val at 1:2:1.2 or 2:1:1 seems to be recommended to improve the impaired protein-nutritional status in liver cirrhosis.

Amino Acids, Branched-Chain↗
PubMed1989

Immunohistochemical demonstration of complement components in formalin-fixed and paraffin-embedded renal tissues.

Although there are many articles describing the detection of complement components in formalin-fixed and paraffin-embedded renal tissues, it is still difficult to obtain reproducible results. The authors determined the optimal conditions for detecting complement components in routine paraffin sections by the avidin-biotin-peroxidase complex method and concluded that proteolytic digestion of the deparaffinized sections was crucial to detect complement and to preserve tissue structures. The optimal proteolytic digestion was a 15-minute incubation at 37 degrees C in trypsin solution, 0.5 mg/ml, pH 7.6. Under these conditions, all of the complement components so far studied (C1q, C1s, C4, C3c, C3b, C5, C6, C9, and properdin) were detected without significant destruction of tissue structures in 52 renal biopsy specimens from patients with various forms of glomerulonephritis. Immunohistochemistry using the avidin-biotin-peroxidase complex method was equivalent to indirect immunofluorescence and superior to direct immunofluorescence in utility and was useful in the diagnosis of glomerular diseases.

Complement System Proteins↗
PubMed1989

Suppression of catecholamine-induced abnormal pacemaker activities by magnesium ion in guinea pig cardiac muscle cells.

The effect of magnesium ion on the abnormal pacemaker activity of guinea pig ventricular muscle cells depolarized by 27 mM K+ was studied. Isoproterenol produced a small depolarization in the resting membrane and elicited automatic repetitive action potentials at higher concentrations in the presence of 0.2 mM Ba2+. This model was used to assess the antiarrhythmic effect of magnesium ion on cardiac muscle cells. Isoproterenol concentrations needed for depolarization alone or for depolarization plus automatic activity were taken as a basis for evaluation. The responsiveness of muscle cells to isoproterenol was suppressed significantly by increasing the magnesium concentration. It is concluded that magnesium ion may have an antiarrhythmic effect on partially depolarized cardiac muscle cells.

Animals↗
PubMed1988

Expression and modulation of a retrovirus-associated antigen by murine melanoma cells.

The antigen recognized by the monoclonal antibody MM2-9B6 is specific for melanomas originating in C57BL/6 mice. It is expressed by three melanomas of independent origin and not by normal or fetal tissues, by a wide variety of other nonmelanoma tumors in C57BL/6 mice, or even by melanomas syngeneic to other strains of mice. We have demonstrated that the expression of the relevant antigen is dependent on the replication and budding of a B-tropic ecotropic murine retrovirus. The relationship between the expression of this virus and carcinogenic progression may yield important insights into the cascade of events leading to neoplastic transformation.

Animals↗
PubMed1988

Two distinct mechanisms involved in the infiltration of lymphocytes into tumors.

We have analyzed the mechanism controlling the infiltration of lymphocytes into tumor tissues. W3/25 (+) (helper/inducer phenotype) T cells obtained from tumor tissues of T-9 sensitized rats produced soluble factors. We demonstrated that the soluble factors were responsible for the infiltration of T lymphocytes into tumor tissues by using a modified Boyden chamber technique. We established a system in which we stained filters of the Boyden chamber by an immunoperoxidase technique, thus directly determining the phenotype of cells that had actually migrated into the filters in response to the soluble factors. Upon fractionation of soluble factors produced by W3/25 (+) T cells, four peaks of lymphocyte migration factor (LMF) activity were detected. Peaks B and C exhibited strong LMF activity and specifically attracted R1-10B5 (+) (suppressor/killer phenotype) T cells. Thus, the infiltration of R1-10B5 (+) T cells into tumor tissues was partly explained by LMF produced by tumor-infiltrating W3/25 (+) T cells. The expression of a putative receptor for LMF by lymphocytes may also influence the degree of lymphocyte infiltration into tumors.

Animals↗
PubMed1988

Actions of flunarizine dihydrochloride on the electrical activity of isolated guinea-pig papillary muscle and rabbit sino-atrial node.

Effects of flunarizine on electrophysiological properties of isolated guinea-pig papillary muscles and rabbit sino-atrial nodes were examined using conventional microelectrode and double-microelectrode voltage clamp methods. Although flunarizine did not affect the maximum rate of rise of the action potential (Vmax) in fast response fibers, the compound depressed the slow action potentials of K+-depolarized papillary muscle (at above 10 microM) and reduced the automaticity of sino-atrial node (at above 3 microM). In voltage clamp experiments, flunarizine selectively suppressed the slow inward current of sino-atrial node specimens. It is concluded that relatively high concentrations of flunarizine directly modify the electrical activity of isolated mammalian myocardium via a suppression of Ca2+ influx through the cell membrane.

Action Potentials↗
PubMed1988

[Coronary artery tone assessed by the administration of ergonovine maleate and nitrates].

Angiographic changes caused by administering ergonovine maleate (EM) and nitrates were quantitated in 136 patients without significant coronary artery disease. Percent coronary artery (CA) narrowing was calculated in 67 patients with a negative EM test (Group A) and 69 patients with a positive EM test (Group B) as follows: (Formula; see text) In both groups, coronary artery narrowing before and after EM did not differ among the proximal, middle or distal segments of each coronary artery. The measurements of the right coronary artery were greater than those of the left anterior descending artery (p less than 0.01 after EM, p less than 0.05 before EM), and those of the left main trunk were markedly less than those of the other coronary arteries (p less than 0.01). In both groups, coronary narrowing after EM administration was greater than before administration (p less than 0.01). Initial coronary narrowing in Group B was also greater than in Group A (p less than 0.01), similar to the responses for EM. In 19 patients with coronary artery spasm provoked by EM coronary artery narrowing before and after EM was 37 +/- 12% and 69 +/- 23% for coronary arteries with spasm, and 30 +/- 13% and 42 +/- 16% for those without spasm. Not only after, but also before EM administration, coronary narrowing was greater in the arteries with spasm than in those without spasm (p less than 0.01). Furthermore, the arteries without spasm showed greater sensitivity to EM and nitrates than did the arteries of the control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Vessels↗
PubMed1987

Heterogeneous expression of a murine B16 melanoma-associated antigen correlates with cell cycle.

A murine monoclonal antibody (MM2-3C6) that reacts with a B16 murine melanoma-associated membrane antigen was used to study the relationship of antigen expression to the cell cycle. Dual-parameter flow cytometric measurements of membrane antigen and DNA revealed that antigen-positive cells were present throughout the cell cycle. Peak antigenic expression was noted during the late log phase of the cell growth curve with negligible antigen-negative population. The emergence of a distinct antigen-negative population (30%-40%) was noted in the late stationary phase. Cell cycle analysis indicated that the negative subpopulation was restricted to the G0/G1 phase, thus, demonstrating antigenic heterogeneity within the tumor cell population. Cell sorting was performed to analyze the origin of such heterogeneity. Following two sequential sortings, the antigen-negative cells became antigenic upon reculture. Again, at the late stationary phase, a distinct antigen-negative population (30%-40%) emerged. The sorted antigen-positive cells showed flow cytometric profiles identical to the sorted antigen-negative population upon reculture. Therefore, in this murine model, it appears that antigen expression is cell cycle dependent and such expression seems to be associated with proliferation.

Animals↗
PubMed1987

Malignant lymphoma, large cell immunoblastic clear cell showing unusual histologic picture.

A case of malignant lymphoma, large cell, immunoblastic clear cell (WF) in a 59-year-old woman was reported. This patient showed no remarkable symptoms except generalized lymphadenopathy and slightly elevated serum levels of IgG and IgM. Histologic examinations were performed twice at about 6 months interval. Marked differences were noticed between the period, and they were histopathologically interesting and unusual findings. By immunological staining in situ, T-clear cells showed a subset marker of helper/inducer's characteristics. It was suggested that this case was different from AILD-like T-cell lymphoma in histogenesis. The results of marker study and the changes in histopathological morphology among two biopsied specimens were presented.

B-Lymphocytes↗
PubMed1987

Electrophysiological study of cibenzoline in voltage-clamped rabbit sinoatrial node preparations.

Effects of cibenzoline (0.1-30 microM) on membrane potentials and currents were investigated in rabbit sinoatrial node cells using conventional microelectrode and double microelectrode voltage clamp methods. Cibenzoline reduced the heart rate, the maximum rate of rise and the action potential amplitude in a dose-dependent manner. At the same time, the action potential duration at half-amplitude was prolonged, and the slope of phase 4 depolarization was decelerated. The voltage clamp experiment revealed that cibenzoline (7-30 microM) depressed the slow inward current, the time-dependent potassium outward current and the hyperpolarization activated current. Neither the kinetic variable of the time-dependent potassium outward current nor the decay time of the outward current tail was altered by the drug perfusion. The results suggest that cibenzoline exerts a depressant effect on the electrical activity of sinoatrial node cells and that the depression of the currents induced by cibenzoline is due to a reduction in conductances of the current systems.

Action Potentials↗
PubMed1985

Heterogeneity of cutaneous T-cell lymphoma. Phenotypic and ultrastructural characterization of four unusual cases.

This study characterized, by means of immunocytochemistry and electron microscopy, four cases of "unusual" cutaneous T-cell lymphoma (CTCL) other than classical mycosis fungoids and Sézary syndrome. Cases 1, 2, and 4 were diffuse lymphoma of a pleomorphic type, and Case 3 was of a mixed type. Case 4 shared a feature common to pagetoid reticulosis. A fairly large number of inflammatory cells were seen in Cases 1, 3, and 4. Functionally, the neoplastic cells of Cases 1, 3, and 4 were of a helper/inducer T-cell subset, whereas those of Case 2 were of a suppressor/cytotoxic T-cell type. Epidermotropic cells with pagetoid growth in Case 4 failed to show these specific surface phenotypes, although they still retained pan T-cell markers. Neoplastic large or intermediate-sized cells revealed a marked difference in the development of cytoplasmic organelles and their nuclear profiles, ranging from a few simple indentations (Cases 2 and 3) to forms with many deep indentations (Case 1) and highly cleaved shapes (Case 4). All of these cells, however, possessed dense-cored granules located in a portion of the cytoplasm. This study indicated the clinicopathologic and immunologic heterogeneity of CTCL, which may be classified, according to the reactivity with monoclonal antibodies and the fine structural features, into subtypes that correspond to functionally distinct subsets of T-cells and their stages or types of differentiation.

Adult↗