T Shimokama

University of Tsukuba, Tsukuba, Ibaraki-ken, Japan

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Publications (44)123.71 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: There have been several reports of cases of renal amyloidosis with glomerular crescents. However, it is not clear whether the association is fortuitous or pathogenic related. The present study analyzed 105 cases of renal amyloidosis (61 autopsy cases and 44 biopsy cases) and found glomerular crescents in 14 (13.3%) cases. Among the 14 cases with crescents, a female predominance was noted (male: female, 3: 11) and rheumatoid arthritis was the most common primary disease of amyloidosis. Immunohistochemical analysis demonstrated amyloid protein of AA type in 12 cases. According to the histologic classification, there were 11 cases of mesangial nodular type, which was almost exclusively accompanied by AA amyloid deposition. Of note, the incidence of crescents neither correlated with the extent of amyloid deposition nor the presence of nephrotic syndrome. By contrast, localization of amyloid deposition was closely related to crescent formation. Moreover, electron microscopic observation displayed rupture of the glomerular basement membrane at the site of amyloid deposition. Our results indicated that glomerular crescents were more frequently associated with renal amyloidosis than previously appreciated. Rupture of the fragile glomerular basement membrane by amyloid deposition, as revealed by immunostaining and electron microscopy, may be the mechanism of crescent formation. We suggest that glomerular crescents are a distinct pathology associated with renal amyloidosis, not fortuitous conditions.
    Pathology International 04/2001; 51(3):179-86. · 1.72 Impact Factor
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    S Iwasa, J Fan, T Shimokama, M Nagata, T Watanabe
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    ABSTRACT: This study was designed to analyze the distribution and localization of endothelin-1 (ET-1) and ET receptors (ET(A) and ET(B)) at different stages of human atherosclerotic lesions by immunohistochemistry. Compared with ET(A) receptors, there was increased immunoreactivity of ET-1 and ET(B) receptor in both unfoamy and foamy macrophages and T lymphocytes in fatty streak and fibrous plaque lesions. In addition, medial SMCs located just beneath the foam cell lesions revealed a higher intensity of ET(B) receptor immunoreactivity than those located beneath the normal-looking intima without foam cells. In fibrous plaques, intimal SMCs near foam cells showed an increased density of ET receptors with predominant ET(B) immunoreactivity. In the areas where SMCs showed ET(B) receptor, ET-1 immunoreactivity was also enhanced. These results suggest that accumulation of foamy macrophages and T lymphocytes may modulate the switching of ET receptor subtypes from ET(A) to ET(B) in vascular SMCs. and that the enhanced ET system mediated by ET(B) receptors may play active roles in the progression of atherosclerosis.
    Atherosclerosis 10/1999; 146(1):93-100. · 3.71 Impact Factor
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    ABSTRACT: In monoclonal IgG cryoglobulinemia, two types of crystallization have been demonstrated with electron microscopy at high magnification. In contrast, little information is available on well-defined crystallization in cases of monoclonal IgM cryoglobulinemia. We present a case of pure monoclonal IgM kappa cryoglobulinemia and rapidly progressive glomerulonephritis occurring in a 75-year-old woman. We detected unequivocal formation of fibrillar crystal structure within intraglomerular macrophages on electron microscopy: the structure accords with that in a case of monoclonal IgG cyroglobulinemia described in the literature.
    Clinical nephrology 06/1998; 49(5):325-7. · 1.29 Impact Factor
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    ABSTRACT: We report here a case of severe membranoproliferative glomerulonephritis with a singular high titer of anticardiolipin antibody (aCL). A 19-year-old Japanese female was admitted to Tsukuba Gakuen Hospital after complaining of general edema for 5 months. She had no past history of thrombosis, thrombocytopenia, or spontaneous abortion. Laboratory findings revealed that she had nephrotic syndrome and moderate renal dysfunction. Immunological test showed a high titer of aCL with a high-normal limit of antinuclear antibody, negativity for anti-beta(2) glycoprotein I antibody and negativity for anti-DNA antibody. In the renal biopsy tissue, most glomeruli showed global sclerosis and the remaining glomeruli revealed membranoproliferative change with crescent formation. Steroid therapy with warfarin and dipyridamole was effective and her renal function improved gradually. This case lacked the typical symptoms of primary antiphospholipid syndrome and did not satisfy the criteria of SLE. In spite of these findings, the singular high titer of aCL with membranoproliferative glomerulonephritis characterized this case.
    Nippon Jinzo Gakkai shi 03/1998; 40(2):54-9.
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    ABSTRACT:  The renin-angiotensin system has a pivotal role in hypertension. The Tsukuba hypertensive mouse (THM; a transgenic mouse carrying human genes for both renin and angiotensinogen) was generated to allow further examination of the renin-angiotensin system in a variety of pathologic conditions. We evaluated the development of renal lesions in these mice and in controls by morphometric, immunohistochemical and ultrastructural methods. Blood pressure was significantly higher in THM than in control mice; 1 year after birth, it was approximately 40 mmHg higher. The kidney-to-body weight ratio was also higher in THM than in control. Morphometrical analysis revealed that the glomerular sclerosis index was significantly elevated in THM with 10% of the glomeruli sclerotic at 18 months. The grade of vascular lesion and the frequency of fibronoid arteritis of the kidney exhibited the same tendency as the glomerular sclerosis index. Murine renin was located exclusively in the juxtaglomerular apparatus, whereas human renin was expressed not only in the juxtaglomerular apparatus, but also in periarteriolar smooth muscle cells and in mesangial and epithelial cells of the glomeruli. Light and electron microscopy revealed significant fibrinoid arteritis of the kidney in THM and also ”onion skinning”, both pathognomonic for malignant nephrosclerosis. THM may be an excellent model of human malignant hypertension.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 01/1998; 432(2):169-175. · 2.68 Impact Factor
  • Q Nie, J Fan, S Haraoka, T Shimokama, T Watanabe
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    ABSTRACT: To investigate the mechanism(s) for mononuclear cell recruitment in the arterial wall during the development of atherosclerosis, we studied intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) expression in aortic intima from diet-induced hypercholesterolemic rats. ICAM-1 was barely found in the aortic walls from rats fed a normal chow diet; however, in rats on a cholesterol-rich diet for 4 weeks, ICAM-1 expression was markedly enhanced in the intimal endothelial cells of aortas. Enhanced expression of ICAM-1 on endothelial cells especially along the cellular borders in the abdominal aorta was almost invariably associated with increased adherence of mononuclear cells. Compared to control animals, in hypercholesterolemic rats, the numbers of intimal macrophages and T lymphocytes adhering to the "lesion-prone" areas of the abdominal aorta were significantly increased by 5.9-fold (p < 0.001) and 2.2-fold (p < 0.001), respectively. More than 85% of adherent macrophages exhibited LFA-1 antigen on the cellular membrane surface as assessed by immunostaining. To examine the participation of ICAM-1 and LFA-1 in adherence and migration of mononuclear cells, we administered monoclonal antibodies (mAb) against either ICAM-1 or LFA-1 into hypercholesterolemic rats after they were fed a cholesterol-rich diet for 2 weeks. Two weeks after the mAb treatment, the number of macrophages adhering to the intima was significantly inhibited by 42% (p < 0.001) with anti-ICAM-1 mAb and by 31% (p < 0.001) with anti-LFA-1 mAb compared to controls injected with mouse IgG. Combined injection with these two mAb increased the reduction of the number of macrophages in the intima to 58%. Furthermore, we found that the decrease in the number of macrophages that adhered to the intima was almost exclusively due to the reduction of LFA-1-positive macrophages. These results suggest that the ICAM-1 and LFA-1 pathway is involved in mononuclear-endothelial cell interaction during cholesterol-rich diet-induced atherogenesis.
    Laboratory Investigation 12/1997; 77(5):469-82. · 3.96 Impact Factor
  • S Haraoka, T Shimokama, T Watanabe
    Annals of the New York Academy of Sciences 05/1997; 811:515-8. · 4.38 Impact Factor
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    ABSTRACT: We report a patient with Churg-Strauss syndrome-associated rapidly progressive glomerulonephritis concurrent with diabetes mellitus. The patient was a 64-year-old woman who was admitted to our hospital because of a glove and stocking type hypesthesia and numbness, multiple purpurae on both legs, and renal insufficiency with hematuria and proteinuria. Renal biopsy revealed necrotizing crescentic glomerulonephritis accompanied by necrotizing arteritis, marked eosinophilic infiltration of the interstitium, and diffuse and nodular diabetic glomerulosclerosis. Cyclophosphamide and steroid therapy succeeded in improving her neurologic symptoms as well as retarding the deterioration in renal function. No clinical manifestations suggestive of a recurrence of Churg-Strauss syndrome have been observed during the one-year follow-up period.
    Internal Medicine 02/1997; 36(1):68-72. · 0.97 Impact Factor
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    ABSTRACT: The potentials of the two major histological types of gastric carcinoma to invade through extracellular matrices were studied with cell lines. We found that the invasive potential of intestinal-type carcinoma cells (MKN-28 and MKN-74) were higher than those of diffuse-type carcinoma cells (MKN-45 and KATO-III). To investigate whether the alpha 2 and alpha 6 integrin adhesion molecules are responsible for, or involved in carcinoma invasion. We further studied alpha 2 and alpha 6 expression patterns in these two types of cell line. Although fluorescence-activated cell sorting analysis revealed that all cells examined invariably expressed these integrin molecules, their expressional patterns were different among different cell lines. The intestinal-type carcinoma cells expressed integrins mainly along the cell-cell contact region, whereas the diffuse-type carcinoma cells showed a diffuse cytoplasmic pattern of integrin expression. Invasion by MKN-28, MKN-74 and MKN-45 cells through reconstituted basement membrane or type I collagen gel was significantly inhibited (P < 0.05) by 50 micrograms/ml anti-(alpha 2 integrin) or anti-(alpha 6 integrin) monoclonal antibodies. Our results suggest that active invasiveness is stronger in the intestinal-type than in the diffuse-type carcinoma cells and that alpha 2 and alpha 6 integrins play important roles in invasion of both types of gastric carcinoma cell lines.
    Journal of Cancer Research and Clinical Oncology 02/1997; 123(6):310-6. · 2.91 Impact Factor
  • T Watanabe, S Haraoka, T Shimokama
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    ABSTRACT: Recent studies have revealed that atherosclerosis bears several similarities to chronic inflammation. One of the earliest events in both human and experimental atherosclerosis is adhesion of monocytes and T lymphocytes to endothelial surface followed by their migration into the intima. This intimal recruitment of blood derived cells, coupled with the enhanced endothelial permeability to plasma proteins, indicates a potential role for inflammatory mechanisms in early atherogenesis. Colocalization of T lymphocytes and macrophages in all stages of human atherosclerosis, from grossly normal prelesional intima to fully advanced atheromatous plaques, and expression of cytokines and MHC class II antigens by many types of cells of the lesion provide further evidence that atherosclerosis has both the inflammatory and immune nature. The presence of T lymphocytes and macrophages in pairs with a close contact to each other suggests that cognate cell to cell interaction also plays a pivotal role in the pathogenesis of atherosclerosis. It seems conceivable that the T lymphocyte-macrophage interaction particularly takes place in the areas where atherosclerotic lesions are in progress or being active. The pathogenic potentials of immunologic factors are fruitful subjects for further investigation.
    International Journal of Cardiology 09/1996; 54 Suppl:S51-60. · 6.18 Impact Factor
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    ABSTRACT: Our previous studies demonstrated the morphological heterogeneity of endothelial cells (ECs) and the emergence of large multinucleated ECs in human and animal atherosclerotic lesions. To investigate the functional alteration of ECs in diet-induced atherosclerosis, immunoreactive endothelin-1 (irET-1) release by ECs of the rabbit aorta was correlated with scanning electron microscopy. Rabbits were fed a cholesterol diet for 12 weeks: by scanning electron microscopy, the area of ECs in the aorta increased in the hypercholesterolemic (HC) group as atherosclerosis progressed. Cultured ECs of the HC group released significantly more irET-1 than ECs of the control. The plasma irET-1 level was also elevated in the HC group. The results obtained suggest that accelerated secretion of ET-1 by ECs contributes to the development of atherosclerotic vascular lesions.
    Pathobiology 02/1996; 64(6):328-32. · 1.95 Impact Factor
  • T Shimokama, S Haraoka, T Watanabe
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    ABSTRACT: Modern techniques of investigation have revealed several similarities between atherosclerosis and chronic inflammation, and that immune mechanisms seem to operate in the incipient and subsequent phases of atherosclerosis. In the present study, the fate and morphogenesis of human atherosclerosis was considered, and the immune aspects of atherogenesis were analysed, using fresh human aorta obtained from autopsy cases. One of the earliest changes in the grossly normal, lesion-prone area of the aorta from young cases (prelesional changes) was the infiltration of blood-borne T lymphocytes and monocytes/macrophages beneath the endothelium. Cell-populated lesions abounding in T lymphocytes and macrophages, often bearing signs of activation, with or without cytoplasmic lipids were found in the fatty streaks, cap and shoulder regions of more advanced atheromatous plaques. The ultrastructural observation of cell-rich areas suggested that cognate cell-to-cell interaction plays a pivotal role in atherosclerosis, as well as cytokine-mediated paracrine or autocrine mechanisms. From an immunological perspective, the areas where both cell types are especially numerous and in close proximity are considered to be the areas with an index of disease activeness or progressiveness. Also, the present authors show evidence of clonal expansion of T lymphocytes. It is most likely that the increase of intimal cells was caused by the recruitment of immunocompetent cells from the blood-stream into the intima and by the clonal expansion of T lymphocytes. In addition, dead or dying cells were identified in areas of different stages ranging from prelesional areas to atheromatous plaques. Thus, the initiation and progression of human atherosclerosis appears to be punctuated by brief episodes of immunological events related to cell infiltration, proliferation and death.
    Pathology International 12/1995; 45(11):801-14. · 1.72 Impact Factor
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    ABSTRACT: We have developed a culture system of guinea pig tracheal epithelial cells using the epithelium-denuded human amnion as a source of basement membrane. Culture medium fluid over the epithelial cells was replaced by air after 7-day immersion culture and thereafter maintained for 2 weeks. Electron microscopical observations revealed that the height of epithelial cells and the ratio of ciliated epithelial cells looked like that of normal guinea pigs epithelium growth in 2 weeks after the air interface, but that no goblet cells could be found. In order to study cell polarity, we measured endothelin-1 levels in the media of apical and basal sides of the epithelial cell monolayer by means of the enzyme-linked immunosorbent assay. The endothelin-1 content of the submucosal side was over 30 times higher than that of the apical side. These findings suggest that ET-1 would be mainly released from airway epithelial cells toward the submucosal side.
    Biochemical and Biophysical Research Communications 06/1995; 210(2):302-9. · 2.28 Impact Factor
  • S Haraoka, T Shimokama, T Watanabe
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    ABSTRACT: Using en face double immunostaining coupled with electron microscopy, we studied the temporal and spatial distribution of T lymphocytes and macrophages during the development of atherosclerosis in a diet-induced rat model fed an atherogenic diet for 2-40 weeks. T lymphocytes and macrophages adhered to the aortic surface by 2 weeks on the diet, with subsequent migration under the endothelium, and formed a fatty streak-like lesion. Analysis of the cellular components revealed that infiltration of T lymphocytes was most prominent in the incipient phase of lesion formation accounting for 60%, 29% and 34% of mononuclear cells appearing in 2-week lesions of the superior thoracic, inferior thoracic and abdominal segments of the aorta, respectively. After the incipient phase, the relative number of T lymphocytes in the three segments of the aorta showed a slow decline; the proportion of T lymphocytes to macrophages was approximately 1:3 to 1:4 in 10- to 20-week lesions. An overall view of the lesional cells often demonstrated direct cellular contact between T lymphocytes and macrophages. Further, OX6/ED1 double immunostaining demonstrated that Ia antigen was expressed on most macrophages. In later stages, breakdown of foamy macrophages occurred, and the extracellular accumulation of lipids and cell debris became prominent. The results demonstrated that in the diet-induced rat model, together with macrophages, large numbers of T lymphocytes participated in all stages of aortic lesions, initially adhering to the surface at prelesional stages and later as the principal component of the atherosclerotic lesion. It is possible that the method described here will provide a good tool for examining the role of T lymphocytes in atherogenesis.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 02/1995; 426(3):307-15. · 2.68 Impact Factor
  • Annals of the New York Academy of Sciences 02/1995; 748:40-55; discussion 55-6. · 4.38 Impact Factor
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    ABSTRACT: A 76-year-old woman with abdominal aortic aneurysm was referred to our hospital with a complaint of abdominal pulsatile mass. CT and angiogram revealed infrarenal abdominal aortic aneurysm (AAA) with right common iliac aneurysm. AAA was replaced with the bifurcated Dacron graft and iliac aneurysm was resected concomitantly. A focal perforation of intima and medial wall hematoma were found in the iliac aneurysm. These findings corresponded with penetrating atherosclerotic ulcer (PAU). PAU in the abdominal aorta may form the abdominal aortic false aneurysm, and may cause the rupture of aneurysm. It is an critical sign of "aortic catastrophe".
    Nippon Geka Gakkai zasshi 01/1995; 95(12):911-4.
  • T Shimokama, S Haraoka, T Watanabe
    Journal of atherosclerosis and thrombosis 02/1994; 1 Suppl 1:S14-20. · 2.93 Impact Factor
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    ABSTRACT: We investigated the aortic endothelial cells of cholesterol-fed rabbits, using scanning electron microscopy and a cell culture technique. Rabbits were given a 1% cholesterol diet intermittently for up to 40 weeks. In these animals, the area of endothelial cells was increased and the cells showed polymorphism in relation to the progression of atherosclerosis. In animals fed the cholesterol diet for 12, 28 and 40 weeks, the average area of the endothelial cells was 436 +/- 15, 762 +/- 153, and 836 +/- 165 microns2, respectively. In the cholesterol-fed 40-week group, in particular, giant endothelial cells, measuring more than 1200 microns2, accounted for 14% of the population. In animals fed a standard diet there was no significant difference in endothelial cell morphology between control 0-week and control 40-week groups; in both, the luminal surface of the thoracic aorta formed a homogeneous sheet covered by small rhomboidal endothelial cells, the area of most being less than 400 microns2. Primary cultured endothelial cells harvested from those control groups were mononuclear typical small cells with a centrally located nucleus; the proportion of binucleated cells was less than 2% and no multinucleated giant cells with three or more nuclei were detected. Endothelial cells from the cholesterol-fed groups, however, contained larger numbers of binucleated cells, with the number increasing in proportion to the duration of cholesterol feeding. The major distinguishing feature of the endothelial cells in the cholesterol-fed groups was the presence of multinucleated giant cells with three or more nuclei; these accounted for 2.3% and 3.3% of the total cell population in the cholesterol-fed 28- and 40-week groups, respectively. No bromodeoxyuridine uptake was found in the nuclei of the cultured multinucleated giant cells. Heterogeneity of endothelial cells, with the concomitant appearance of multinucleated giant cells, emerges with the progression of diet-induced atherosclerosis. The morphological alterations of endothelial cells observed in the present study intimately reflect changes in their function associated with the progression of atherosclerotic lesions.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 02/1994; 425(5):521-9. · 2.68 Impact Factor
  • J Fan, T Shimokama, O Tokunaga, T Watanabe
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    ABSTRACT: Intimal infiltration of lipid-filled macrophages (M psi s) is an important event in the pathogenesis of atherosclerosis. To better understand M psi functions, a model for the extravascular in vivo generation of foam cells in rat peritoneal cavities was utilized. Morphologic alterations, intracellular cholesterol accumulation, subpopulation, activation and proliferative properties of M psi from hypercholesterolemic rats (HM psi s) were compared with M psi s from normal rats (NM psi s). HM psi s revealed a significant increase of cholesterol mass in the cytoplasm; 65% of HM psi s were loaded with various amounts of oil-red-O-stainable lipid droplets which were barely identified in NM psi s. Ultrastructurally, accumulated lipid droplets in HM psi s were either membrane-bound or membrane-free in the cytoplasm. Further biochemical analysis revealed that cellular levels of total cholesterol, free cholesterol, and cholesteryl esters in HM psi s were increased 6-, 8-, and 4-fold, respectively. As to the M psi subpopulation, there was a significant increase of Ia-antigen-positive cells in HM psi s (15.8 vs. 8.8%), indicating that these cells were in a state of activation. To investigate the mitotic activity, the proliferative potential of M psi s was determined both in vivo and in vitro using monoclonal anti-bromodeoxyuridine (anti-BrdU) antibody to detect BrdU incorporated into cell DNA. However, both NM psi s and HM psi s showed little proliferation; proliferative indices were less than 2%. This implies that M psi s are barely replicating, and hypercholesterolemia does not stimulate M psi s in this aspect.(ABSTRACT TRUNCATED AT 250 WORDS)
    Pathobiology 02/1994; 62(1):1-7. · 1.95 Impact Factor
  • S HARAOKA, T SHIMOKAMA, T WATANABE
    Atherosclerosis 01/1994; 109:100-101. · 3.71 Impact Factor