Biomedical subjects

Y Tsukamoto

Publications and source records attributed to Y Tsukamoto.

At least 73 records · Page 4Linked to original sources

PubMed2000

Epithelial cell kinetics in the inflammatory process of chicken trachea infected with infectious bronchitis virus.

All stages of degeneration and regeneration in chicken tracheal epithelium were studied morphologically following an intratracheal inoculation of infectious bronchitis virus (IBV). Viral antigen was detected in the cytoplasm of tracheal epithelium from 1 to 7 days post-inoculation (d.p.i.) with a peak on 3 d.p.i. At 1 d.p.i., almost all epithelial cells were involved in the degeneration. At this time, labelling index of bromodeoxyuridine (BrdU) in the basal cells showed significantly high value compared with control. At 2 and 3 d.p.i., a great number of basal cells were recognized, but the BrdU labelling index tended to decrease. At 4 and 5 d.p.i., the BrdU labelling index of basal cells significantly decreased than 1 d.p.i., and a few number of regenerated immature ciliated epithelia appeared. At 6 to 11 d.p.i., the ciliated columnar epithelia increased rapidly in number, and returned to the normal appearance except for non-ciliated patch by 13 d.p.i. These results suggested that the tracheal epithelial cells infected with IBV degenerated within 24 hours and proliferating activity of basal cells functioned immediately, and 3 to 4 days later, these basal cells were differentiated to the ciliated epithelia.

Animals↗

PubMed2000

Kinetics of lymphocytic subsets in chicken tracheal lesions infected with infectious bronchitis virus.

The kinetics of T-cells (CD3 positive (+), CD4+ and CD8+ cells) and B-cells (IgG+, IgM+ and IgA+ cells) in chicken trachea were studied immunohistochemically and histopathologically following an intratracheal inoculation of infectious bronchitis virus (IBV). Viral antigen was detected in the cytoplasm of tracheal epithelium from 16 hr to 6 days post-inoculation (p.i.) with a peak on 4 days p.i. A few IgG+, IgM+ and IgA+ cells were detected in the submucosa from 8 hr p.i. Thereafter IgG+ and IgM+ cells were gradually increased in number, and dramatically increased from 3 days p.i., peaked on 4 days p.i., and gradually decreased after 5 days p.i. IgA+ cells were detected in a small number than IgG+ and IgM+ cells during the all experimental period. These B cells mainly existed in the lamina propria, and some cells were recognized in the interepithelial space. After 14 days p.i., small number of IgG+ and IgM+ cells were detected in the germinal center of lymph follicles in the lamina propria. From 24 to 60 hr p.i., a few number of CD3+, CD4+ and CD8+ cells were detected at the perivascular area in the lamina propria. After 3 or 4 days p.i., each positive T-cells increased rapidly in number, and reached on the peak at 5 days p.i. CD3+, CD4+ and CD8+ cells tend to distribute diffusely, perivascular area, and surrounding area of CD4+ cells, respectively. CD4+ cells were dramatically decreased from 7 days p.i., and CD3+ and CD8+ cells were decreased from 14 days p.i. No T-cells were detected in the lymph follicles in the lamina propria.

Animals↗

PubMed2000

Distribution of cells immunopositive for AM-3K, a novel monoclonal antibody recognizing human macrophages, in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits.

The monoclonal antibody AM-3K, which was developed using human pulmonary macrophages as the immunogen, immunocytochemically labels most human macrophages except for blood monocytes and dendritic cell populations. AM-3K also shows cross-reactivity in some animal species. To evaluate the usefulness of AM-3K, the present study investigated the detailed distribution of AM-3K-immunopositive macrophages in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits. Zamboni's solution-fixed, paraffin-embedded sections were the most available for the immunocytochemistry with AM-3K. In all animal species examined, AM-3K labeled most macrophages in splenic red pulp, lymph node sinuses and thymus, and tissue macrophages in the interstitium of various organs and sites such as the kidneys, lungs, heart, pancreas, intestines, and skin. Alveolar macrophages and perivascular microglial cells were also immunoreactive for AM-3K. Interestingly, Kupffer cells of dogs, cats, and horses were labeled for AM-3K, but those of cattle, pigs, and rabbits were not. Furthermore, in tumor tissues and inflammatory lesions such as liver fibrosis and encephalomalacia that were obtained from dogs, infiltrating macrophages were stained with AM-3K, but not all infiltrating macrophages reacted to AM-3K. In addition, only 30-50% of pulmonary and peritoneal macrophages obtained from cats and dogs were reactive for AM-3K. AM-3K did not react with blood monocytes, dendritic cell populations, and osteoclasts. These observations indicate that AM-3K specifically labels most exudate and tissue macrophages in the animal species examined. However, the expression of antigens recognized by AM-3K on macrophages may be dependent on differential maturation stages or different functions evoked by some conditions. AM-3K immunoreaction products were seen on the cytoplasmic membrane of macrophages by immunoelectron microscopy. AM-3K would be useful for detection of macrophage populations in the animal species examined here.

Animals↗

PubMed1999

Cloning and characterization of a novel human gene encoding a zinc finger protein with 25 fingers.

This study reports cloning and characterization of a human cDNA encoding a novel human zinc finger protein, ZFD25. ZFD25 cDNA is 6118 bp long and has an open reading frame of 2352 bp that encodes a 783 amino acid protein with 25 C2H2-type zinc fingers. The ZFD25 cDNA also contains a region with high sequence similarity to the Krüppel-associated box A and B domain in the 5'-untranslated region, suggesting that ZFD25 belongs to the Krüppel-associated box zinc finger protein family. The ZFD25 gene was localized to chromosome 7q11.2. Northern blot analysis showed that ZFD25 was expressed in a wide range of human organs. In cultured endothelial cells, the mRNA level was decreased upon serum starvation.

Amino Acid Sequence↗

PubMed1999

Cytoplasmic domain is not essential for the cell adhesion activities of gicerin, an Ig-superfamily molecule.

Gicerin is a cell adhesion molecule in the immunoglobulin (Ig) superfamily and is expressed abundantly during development in the nervous system. It has homophilic cell adhesion activity and also has heterophilic binding activity with NOF (neurite outgrowth factor) and mediates neurite extension. There are two isoforms of gicerin, one with a short (s-gicerin) and the other with a longer cytoplasmic domain (l-gicerin). We have reported that s-gicerin possesses stronger activities than l-gicerin during cell aggregation, in NOF-binding, and in neurite extension. In this study, we established cell lines which expressed a mutant-gicerin whose cytoplasmic domain was deleted and we compared the above three biological activities of the mutant-gicerin with those of s- and l-gicerin. We found that the mutant-gicerin retained all these activities, but the activities were weaker than those of s-gicerin and almost the same as those of l-gicerin. We concluded that the cytoplasmic domain of gicerin is not essential for optimal adhesive activities of gicerin, but might be involved in the regulation of its activities.

Amino Acid Sequence↗

PubMed1999

Expression of gicerin, a cell adhesion molecule, in the abnormal retina in silver plumage color mutation of Japanese quail (Coturnix japonica).

Silver plumage color mutant (B/B) quail has an abnormal retina characterizing the transdifferentiation of retinal pigment epithelium (RPE) following the retinal separation in the early developmental stage. In the present study; (i) the expression of gicerin, an immunoglobulin-superfamily cell adhesion molecule, was examined in the retina of B/B quail. In the wild-type quail, gicerin protein was enriched in the apical membrane (facing the neural retina, NR) of RPE cells on embryonic day (E) 4 and then appeared also in NR cells from E5. However, in the B/B retina, no gicerin expression was found in the transdifferentiation area of RPE prior to the retinal separation. (ii) In addition to this, microinjection of anti-gicerin polyclonal antibody into the eyeball of wild-type quail on E3 caused the retinal separation and induced the transdifferentiation of RPE into new NR. These observations suggest that the decrease of gicerin expression might participate in the retinal separation and RPE-transdifferentiation in B/B quail.

Animals↗

PubMed1999

Involvement of gicerin, a cell adhesion molecule, in development and regeneration of oviduct and metastasis of oviductal adenocarcinomas of the chicken.

Gicerin is a novel cell adhesion molecule in the immunoglobulin superfamily and has both homophilic adhesion and heterophilic adhesive activity to neurite outgrowth factor (NOF), an extracellular matrix protein in the laminin family. We investigated the possible involvement of gicerin in oviductal development, regeneration, and metastasis of oviductal adenocarcinomas of the chicken. In the oviductal epithelium, gicerin was expressed strongly during development, disappeared after maturation, and reappeared during regeneration. NOF was constitutively expressed in the basement membrane of the epithelium. These molecules were expressed strongly in oviductal adenocarcinomas in both primary and metastatic lesions in the mesentery. An anti-gicerin antibody inhibited the attachment of adenocarcinoma cells to the mesentery in vitro. Many cells migrated from adenocarcinoma tissues on NOF, which were inhibited by an anti-gicerin antibody. These results suggest that gicerin might play a role in oviductal development and regeneration and also in the metastasis of adenocarcinomas.

Adenocarcinoma↗

PubMed1999

Sex differentiation of growth hormone-releasing hormone and somatostatin neurons in the mouse hypothalamus: an immunohistochemical and morphological study.

We examine sexual dimorphism in growth hormone-releasing hormone (GHRH) in the arcuate nucleus (ARC), and somatostatin (SS) in the periventricular nucleus (PeN) of the hypothalamus, and investigate when it becomes evident. Using immunohistochemical staining and morphometry, we observed ARC GHRH-immunoreactive (ir) neurons, ARC SS-ir neurons and PeN SS-ir neurons in male and female mice at 5, 20, 30, 40 and 60 days old. The number of ARC GHRH-ir neurons was significantly higher in males than females, after 20 days old. ARC SS-ir neurons showed no significant differences between sexes. On the other hand, PeN SS-ir neurons were significantly more numerous in males at 30, 40 and 60 days than in females. During postnatal development, these GHRH- and SS-ir neurons changed in different patterns from ages 20 to 60 days. The number of ARC GHRH-ir neurons in both sexes decreased from 5 to 20 days, increased until day 40, and then decreased at day 60, while ARC SS-ir neurons in both sexes increased from day 5 to day 60. PeN SS-ir neurons in both sexes increased from days 5 to 20 to 116% in males and 189% in females. Furthermore, in male mice, the increase continued until 40 days of age, while in females, there was no significant difference from days 20 to 60. There were no apoptotic cells; a few proliferating cell nuclear antigen (PCNA) stained cells were found in the ARC and PeN. Our results suggest that the sex difference of ARC GHRH neurons and PeN SS neurons appears by stimulation with testosterone during the development life. The developmental fluctuation in the number of ARC GHRH-ir neurons may not be modulated by testosterone, but by ARC SS neurons.

Animals↗

PubMed1999

150-kDa oxygen-regulated protein (ORP150) suppresses hypoxia-induced apoptotic cell death.

To determine the contribution of 150-kDa oxygen-regulated protein (ORP150) to cellular processes underlying adaptation to hypoxia, a cell line stably transfected to overexpress ORP150 antisense RNA was created. In human embryonic kidney (HEK) cells stably overexpressing ORP150 antisense RNA, ORP150 antigen and transcripts were suppressed to low levels in normoxia and hypoxia, whereas wild-type cells showed induction of ORP150 with oxygen deprivation. Inhibition of ORP150 in antisense transfectants was selective, as hypoxia-mediated enhancement of glucose-regulated protein (GRP) 78 and GRP94 was maintained. However, antisense ORP150 transfectants displayed reduced viability when subjected to hypoxia, compared with wild-type and sense-transfected HEK cells. In contrast, diminished levels of ORP150 had no effect on cytotoxicity induced by other stimuli, including oxygen-free radicals and sodium arsenate. Although cellular ATP content was similar in hypoxia, compared with ORP150 antisense transfectants and wild-type HEK cells, suppression of ORP150 expression was associated with accelerated apoptosis. Hypoxia-mediated cell death in antisense HEK transfectants did not cause an increase in caspase activity or in cytoplasmic cytochrome c antigen. A well recognized inducer of apoptosis in HEK cells, staurosporine, caused increased caspase activity and cytoplasmic cytochrome c levels in both wild-type and antisense cells. These data indicate that ORP150 has an important cytoprotective role in hypoxia-induced cellular perturbation and that ORP150-associated inhibition of apoptosis may involve mechanisms distinct from those triggered by other apoptotic stimuli.

Apoptosis↗

PubMed1999

Effect of vitamin K2 (menaquinone-7) in fermented soybean (natto) on bone loss in ovariectomized rats.

The effect of dietary vitamin K2 (menaquinone-7) on bone loss in ovariectomized (OVX) rats was investigated. OVX rats were freely given experimental diets containing menaquinone-4 (MK-4; 12mg/100g diet) or menaquinone-7 (MK-7; 18.1mg/100g diet) for 24 days; MK-4 and MK-7 were equal in molar concentrations. This feeding caused a remarkable increase of MK-4 and MK-7 concentrations in the serum and femur of OVX rats. OVX-induced decrease in the femoral dry weight and femoral calcium content was prevented by the feeding of dietary MK-4 or NK-7. In separate experiments, OVX rats were freely given experimental diets containing the fermented soybean (natto; including 9.4 microg MK-7/100g diet) without or with added MK-7 (37.6 microg/100g diet) for 77 days. Feeding produced a significant elevation of MK-4 and MK-7 concentrations in the serum of OVX rats. In this case, a significant increase in the femoral MK-4 content was observed but MK-7 was not detected in the femoral tissues. OVX-induced decreases in the femoral dry weight and femoral calcium content were significantly prevented by the feeding of diets containing natto with MK-7 added (37.6 microg/100g diets). This study demonstrates that the intake of dietary MK-7 has a preventive effect on bone loss caused by OVX. This effect may be partly caused by MK-4, which is formed by degradation of MK-7.

Animals↗

PubMed1999

N-glycan structures of murine hippocampus serine protease, neuropsin, produced in Trichoplusia ni cells.

N-glycans of neuropsin (serine protease in the murine hippocampus) expressed in Trichoplusia ni cells were released from the glycopeptides by digestion with glycoamidase A (from sweet almond), and the reducing ends of the oligosaccharides were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a two dimensional high-performance liquid chromatography (HPLC) mapping technique on two kinds of HPLC columns. Fourteen different major N-glycan structures were identified, of which 6 were high-mannose type (9.1%), and the remaining 8 were paucimannosidic type. The presence of insect specific N-glycan structures containing both alpha1,3- and alpha1,6- di-fucosylated innermost N-acetylglucosamine residue (23.3%), as below, was also confirmed by 600 MHz 1H-NMR spectroscopy.

Animals↗

PubMed1999

Coronary atherosclerosis and interventions: pathological sequences and restenosis.

The primary cause of cardiac morbidity and mortality in developed countries is ischemic (coronary) heart disease. The incidence of this disease is virtually all due to atherosclerosis, and ischemic heart disease is also the most prevalent disease in the industrialized world, causing over 40% of all deaths in the United States and Western Europe. In Japan, the incidence of ischemic heart disease due to coronary atherosclerosis is gradually increasing as well. Compared with the classical nomenclature of atherosclerosis; that is, fatty streak, fibrous plaque and complicated lesions, the term Stary's classification has been universally accepted because it reflects the more recently acquired knowledge about the morphological and biochemical details of the processes in coronary atherosclerosis, which have been obtained by new strategies such as angioscopy, intravascular ultrasound and molecular biological methods. The term Stary's classification has been applied for the coronary atherosclerosis of patients with acute coronary syndrome at the National Cardiovascular Center, for the analysis of predisposing atherosclerosis of these patients. The recent findings regarding acute coronary syndrome resulting from a rupture of coronary atherosclerotic plaques indicate that this syndrome is probably the most important mechanism underlying the sudden onset. It has been found that the risk of plaque rupture may depend more on plaque composition than on plaque size. Plaques rich in soft extracellular lipids and macrophages are possibly more vulnerable to plaque rupture. Two of the goals of the present review are to clarify how plaque disruption occurs and to elucidate the relationship between plaque disruption and coronary risk factors in elderly Japanese patients with acute coronary syndrome. Coronary stents have been shown to be efficacious in the treatment of acute and threatened closure complicating percutaneous transluminal coronary angioplasty (PTCA) and have produced encouraging initial results in the prevention of restenosis. In the autopsy study of restenosis after PTCA, it was observed that dense caps of collagen fibers in the adventitia in the vicinity of the disrupted internal elastic laminae were present in all of the remodeling lesions. It is suggested that remodeling, which resulted in adventitial scarring, is one of the major causative factors of restenosis after PTCA. The long-term success of stenting, however, remains limited by the occurrence of late in-stent restenosis, with an incidence of 20-42% depending on the stent design and the patient population studied. Another aim of the present review is to describe the pathological mechanism of restenosis after PTCA and/or stent replacement and, consequently, the vascular remodeling that occurs around adventitial tissue after PTCA and intimal hyperplasia that is chronically irritated by a foreign body granulomatous reaction after stenting. Finally, the results of the investigation of the effect of a tissue factor pathway inhibitor on the prevention of interventional restenosis is described.

Angioplasty, Balloon, Coronary↗

PubMed1999

Effect of probucol on hypercholesterolemia in renal transplant patients.

BACKGROUND: Hypercholesterolemia is a well-known complication in kidney transplant recipients, although its pathogenesis may be multifactorial. The therapeutic effect of probucol on post-transplant hypercholesterolemia was prospectively evaluated. METHODS: Twelve hypercholesterolemic kidney transplant patients with serum total cholesterol > or = 250 mg/dl without diabetes mellitus or hypoproteinemia were prospectively treated with probucol (250 mg, bid, for three months). Before initiating and at the end of treatment, blood was drawn after at least a 12-hour fast to measure lipids in serum and lipoprotein fractions, apoproteins (apo), lipoprotein fractions, lethicin cholesterol acyl transferase (LCAT), free fatty acids (FFAs), and cholesterol ester. The lipid profiles of 17 healthy subjects were also examined. RESULTS: After treatment with probucol, serum total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and apo AI were significantly decreased, whereas cholesterol ester increased significantly. CONCLUSIONS: Post-transplant hypercholesterolemia is featured with abnormalities in very low-density lipoprotein (VLDL) metabolism. Although HDL cholesterol decreased, probucol might have acted as an antiatherogenic by modulating HDL metabolism and stimulating reverse transfer of cholesterol from peripheral tissue.

Adult↗

PubMed1999

Enhancing effect of dietary vinegar on the intestinal absorption of calcium in ovariectomized rats.

We studied the effect of dietary vinegar on calcium absorption by using ovariectomized rats fed on a low-calcium diet. The apparent absorption of calcium was higher when the rats were fed on a diet containing 1.6% vinegar for 32 days than when fed on a diet without vinegar (P < 0.05). The calcium content in the femur of the rats given diets containing 0.4% and 1.6% vinegar were also higher (P < 0.05). The serum parathyroid hormone level was lower and the crypt depth of the duodenum thicker in the rats fed on a diet containing 1.6% vinegar (P < 0.05). These results suggest that dietary vinegar enhanced intestinal calcium absorption by improving calcium solubility and by the trophic effect of the acetic acid contained in vinegar, which would reduce the bone turnover caused by ovariectomy and be helpful in preventing osteoporosis.

Acetic Acid↗

PubMed1999

Nuclear proliferation in syncytia during avian reovirus replication.

Cultured chick embryonic fibroblasts formed syncytia after infection with avian reovirus (ARV) strain 58-132. Mitotic figures were occasionally observed within the syncytia. In addition, many nuclei in the syncytia incorporated 5-bromo-2'-deoxyuridine (BrdU), a DNA replication marker, indicating that they were in the S-phase of the cell cycle. These observations suggested that the nuclei within ARV-induced syncytia originated from nuclear endomitosis without cell division, as well as from cell fusion.

Animals↗

PubMed1998

Marked, sustained expression of a novel 150-kDa oxygen-regulated stress protein, in severely ischemic mouse neurons.

The 150-kDa oxygen-regulated protein (ORP150) first was described with reference to the central nervous system in cultured astrocytes subjected to dense hypoxia. Subsequently its transcript was found in macrophages within human aortic atherosclerotic plaques, suggesting a role in protecting cells under hypoxic stress. In a mouse model of permanent focal brain ischemia, we aimed to elucidate the constitutive cellular localization in vivo of ORP150 in the central nervous system as well as the sequential alteration in its mRNA and protein expression during this severe ischemic insult. Immunohistochemical study demonstrated that ORP150 protein normally is present predominantly in neurons. The 78-kDa glucose-regulated protein, which is another well-known stress protein retained in the endoplasmic reticulum, also was stained in neurons. During the first 3 h after ischemia, ORP150 antigenicity was markedly enhanced in severely damaged neurons, while the amount of the glucose-regulated protein was decreased. Preceding this change, orp150 mRNA was selectively induced in neurons undergoing postischemic cytoskeletal proteolysis, as early as 1 h after middle cerebral artery occlusion. These results indicated that ORP150 might be regulated by transcriptional level as for many stress proteins, but unlike previously described other stress proteins it was translated in the center of ischemic lesions despite nearly complete energy depletion. In this paper, the biological potentials of ORP150 protein in the setting of brain ischemia in vivo will also be discussed.

Animals↗

PubMed1998

Mathematical modeling to predict the bactericidal effect of processed vinegar on Escherichia coli O157:H7.

The combined effects of acetic acid, temperature and sodium chloride on Escherichia coli O157:H7 inactivation were examined in processed vinegar. To express their effects, quadratic polynomial models were applied. The logarithm transformation of sodium chloride concentration provided a better fit of the data than the use of a non-transformation value. On the basis of this finding, the polynomial models should be distinguished into two types, i.e. the non-sodium chloride model and the sodium chloride model, both of which had high R2 values (0.988 and 0.978, respectively).

Acetic Acid↗

PubMed1998

Microcircuitry and mosaic of a blue-yellow ganglion cell in the primate retina.

Perception of hue is opponent, involving the antagonistic comparison of signals from different cone types. For blue versus yellow opponency, the antagonism is first evident at a ganglion cell with firing that increases to stimulation of short wavelength-sensitive (S) cones and decreases to stimulation of middle wavelength-sensitive (M) and long wavelength-sensitive (L) cones. This ganglion cell, termed blue-yellow (B-Y), has a distinctive morphology with dendrites in both ON and OFF strata of the inner plexiform layer (Dacey and Lee, 1994). Here we report the synaptic circuitry of the cell and its spatial density. Reconstructing neurons in macaque fovea from electron micrographs of serial sections, we identified six ganglion cells that branch in both strata and have similar circuitry. In the ON stratum each cell collects approximately 33 synapses from bipolar cells traced back exclusively to invaginating contacts from S cones, and in the OFF stratum each cell collects approximately 14 synapses from bipolar cells (types DB2 and DB3) traced to basal synapses from approximately 20 M and L cones. This circuitry predicts that spatially coincident blue-yellow opponency arises at the level of the cone output via expression of different glutamate receptors. S cone stimuli suppress glutamate release onto metabotropic receptors of the S cone bipolar cell dendrite, thereby opening cation channels, whereas M and L cone stimuli suppress glutamate release onto ionotropic glutamate receptors of DB2 and DB3 cell dendrites, thereby closing cation channels. Although the B-Y cell is relatively rare (3% of foveal ganglion cells), its spatial density equals that of the S cone; thus it could support psychophysical discrimination of a blue-yellow grating down to the spatial cutoff of the S cone mosaic.

Animals↗