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Biomedical subjects

A Takeda

Publications and source records attributed to A Takeda.

At least 577 records · Page 32Linked to original sources
PubMedDate not supplied

Early proliferative changes in hearts of hypertensive Goldblatt rats: an immunohistochemical and flow-cytometrical study.

Hyperplasia of myocytes in cardiac adaptation is a rare event in the mammalian cardiac muscle. Recent findings support the concept that proliferation of myocytes in the adult mammalian heart may be induced after a prolonged increase in pressure load on the myocardium. To determine whether short-term hypertension leads to hyperplasia of myocyte nuclei in the rat heart renal hypertension was produced in 12 Wistar rats. As soon as hypertension occurred, bromodeoxyuridine (BrdU) (50 mg/kg/day) was injected intraperitoneally on three subsequent days. Twelve sham-operated rats served as controls. After 3 days, the left cardiac ventricle was excised and double-staining with anti-BrdU antibody and propidium iodide was performed to determine the phase of cell-cycle of the BrdU-positive cells by flow-cytometry. Immunohistochemical double-staining with desmin, smooth muscle actin, vimentin, and BrdU was done to classify the BrdU-positive cells. Most of the BrdU-positive cells were in the G0/G1-phase of the cell-cycle, suggesting cell proliferation or DNA-repair have taken place; polyploidy was not observed. In the hypertensive group (4.62% +/- 2.36) significantly more cells incorporated BrdU than in the control group (1.46% +/- 0.96). Immunohistochemically, the majority of the BrdU-positive cells consisted of fibrocytes, smooth muscle cells, and endothelial cells. Only 0.35% +/- 0.26 of cardiac myocytes in the normotensive group showed positive BrdU-staining compared to 0.48% +/- 0.32 in the hypertensive group. This difference was statistically not significant. This study showed that early after onset of hypertension proliferation of non-myocytes, but not of myocytes occurred. DNA synthesis is limited almost completely to the interstitial cells and does not occur in any significant extent in cardiac myocytes. In conclusion, hyperplasia of cardiac myocytes is not observed at early stages of hypertension, but it may develop at a late stage of cardiac adaptation.

Actins↗
PubMedDate not supplied

Elevation of hepatic levels of metallothionein during experimental carcinogenesis.

From the early stage of pancreatic adenocarcinoma in hamsters and also of hepatocellular carcinoma in rats, induced by treatment with N-nitrosobis (2-oxopropyl)amine and 3'-methyl-dimethylaminoazobenzene, respectively, hepatic levels of metallothionein (MT) were found to be continuously elevated. In the hepatoma-induced rats, this elevation preceded that of serum gamma-glutamyl transpeptidase activity, a marker enzyme for hepatocellular carcinoma. These results indicate that, in the course of chemical carcinogenesis, the elevation of hepatic MT level occurred and continued from the early stage of carcinogenesis. This type of elevation of hepatic MT level was also observed in lung metastasis-induced mice. On the other hand, in rats with pancreatitis caused by the administration of deoxycholate, the hepatic level of MT rose only transiently.

Animals↗
PubMedDate not supplied

Creation of an acellular dermal matrix from frozen skin.

At present, one of the treatments of choice for closure of full-thickness skin loss is to use a cultured epidermal autograft when skin loss is extensive. In this study, we investigated a simple method of processing frozen surplus skin to produce an acellular, structurally intact, dermal matrix. First, the acellular dermal matrix prepared from normal human skin (ADM) we processed was observed using a transmission electron microscope and a scanning electron microscope. The matrix maintained the basement membrane complex and the extracellular matrix structure of the dermis despite frozen skin being used. Next, using an animal model, we transplanted the ADM and Pelnac, which is used as a contrast in full-thickness wounds onto nude rats. The dermal matrix supported fibroblast infiltration and neovascularization. These results suggest that skin processed by our simple method has the potential to be used as a dermal template together with the cultured epidermis in the closure of full-thickness wounds.

Animals↗
PubMedDate not supplied

Increased bilirubins and their derivatives in cerebrospinal fluid in Alzheimer's disease.

Bilirubin, an efficient antioxidant, is the end product of the heme cleavage pathway, which is catalyzed by heme oxygenase (HO) and biliverdin reductase. Although an inducible form of HO is overexpressed in the Alzheimer's disease (AD) brain, it has not been determined whether bilirubin metabolism is actually activated or not. In this study, we measured CSF-bilirubins and their derivatives using an enzyme-linked immunosorbent assay with two kinds of anti-bilirubin monoclonal antibodies, designated 24G7 and 5M2. In AD patients, the levels of CSF bilirubin derivatives increased significantly compared with those of controls. This increase was not due to the increased permeability of the blood-brain barrier, because the levels of unconjugated bilirubin were not different between AD and controls. These data may reflect the increase of degraded bilirubin metabolites in the AD brain derived from the scavenging reaction against chronic oxidative stress.

Adult↗
PubMedDate not supplied

Oxidative damage in Alzheimer's disease: the metabolic dimension.

Cell bodies of neurons at risk of death in Alzheimer disease have increased lipid peroxidation, nitration, free carbonyls, and nucleic acid oxidation. These oxidative changes are uniform among neurons and are seen whether or not the neurons display neurofibrillary tangles and, in fact, are acutally reduced in the latter case. In consideration of this localization of damage, in this review, we provide a summary of recent work demonstrating some key abnormalities that may initiate and promote neuronal oxidatave damage.

Alzheimer Disease↗
PubMedDate not supplied

Activation of oncogenic pathways in degenerating neurons in Alzheimer disease.

A number of recent findings have highlighted the similarities between neurogenesis during development and neurodegeneration during Alzheimer disease. In fact, neuronal populations that are known to degenerate in Alzheimer disease exhibit phenotypic changes characteristic of cells re-entering the cell division cycle. In this study, we extended these findings by investigating components of the cell cycle, known to trigger progression through G1 through activation of signal transduction cascades. Specifically, we found that proteins implicated in G1 transition, namely Cdc42/Rac, are upregulated in select neuronal populations in cases of Alzheimer disease in comparison to age-matched controls. Importantly, Cdc42/Rac shows considerable overlap with early cytoskeletal abnormalities suggesting that these changes are an extremely proximal event in the pathogenesis of the disease. Given the functional role of Cdc42/Rac in various cellular processes known to be perturbed in Alzheimer disease, namely cytoskeletal organization, oxidative balance, and oncogenic signaling, it is likely that increased neuronal Cdc42/Rac is highly significant in relation to the pathogenic process and contributes to neuronal degeneration. In fact, these findings suggest that Alzheimer disease is an oncogenic process.

Aged↗
PubMedDate not supplied

Zinc homeostasis and functions of zinc in the brain.

The brain barrier system, i.e., the blood-brain and blood-cerebrospinal fluid barriers, is important for zinc homeostasis in the brain. Zinc is supplied to the brain via both barriers. A large portion of zinc serves as zinc metalloproteins in neurons and glial cells. Approximately 10% of the total zinc in the brain, probably ionic zinc, exists in the synaptic vesicles, and may serve as an endogenous neuromodulator in synaptic neurotransmission. The turnover of zinc in the brain is much slower than in peripheral tissues such as the liver. However, dietary zinc deprivation affects zinc homeostasis in the brain. Vesicular zinc-enriched regions, e.g., the hippocampus, are responsive to dietary zinc deprivation, which causes brain dysfunctions such as learning impairment and olfactory dysfunction. Olfactory recognition is reversibly disturbed by the chelation of zinc released from amygdalar neuron terminals. On the other hand, the susceptibility to epileptic seizures, which may decrease vesicular zinc, is also enhanced by zinc deficiency. Therefore, zinc homeostasis in the brain is closely related to neuronal activity. Even in adult animals and probably adult humans, adequate zinc supply is important for brain functions and prevention of neurological diseases.

Amygdala↗
PubMedDate not supplied

Detection of preoperative serum anti-p53 antibodies in gastric cancer.

The presence of circulating anti-p53 antibodies (p53Ab) was investigated in 81 gastric cancer patients by ELISA. Preoperatively, anti-p53Ab were revealed in 13 cases (16%), including 3 early gastric cancers. No significant correlation of p53Ab with patient age, sex, pathological parameters and tumor markers, such as CEA and CA19-9 was observed, although p53Ab positivity tended to be associated with a higher rate of lymph node metastases (p = 0.073). We have found no significant correlation between p53Ab and poor survival rate (p = 0.325). In conclusion, we have observed that p53Ab are detectable in gastric cancer patients, even at early stages of disease, however, p53Ab have not served as a predictor of poor prognosis in gastric cancer in this series.

Adenocarcinoma↗
PubMedDate not supplied

Does protease inhibitor inhibit complement activation caused by the immune complex associated with islet cell surface antibody?

Sera containing islet cell surface antibody were obtained from seven children with insulin-dependent diabetes mellitus soon after the onset of disease. After incubation of 51Cr-labelled rat islet cells with islet cell surface antibody, human AB-type serum with or without nafamostat mesylate was added before further incubation. Radioactivity in the supernatant was measured to determine complement-dependent antibody-mediated cytotoxicity. Cytotoxicity in untreated sera [mean (+/- SD) 19.4 +/- 4.0%] was significantly (P less than 0.001) inhibited by ethyleneglycoltetraacetic acid (EGTA) (7.1 +/- 4.9%), ethylenediaminetetraacetic acid (EDTA) (2.5 +/- 0.9%) and nafamostat mesylate (2.8 +/- 1.8%). Cytotoxicity of nafamostat mesylate-treated serum was significantly (P less than 0.05) lower than that of EGTA-treated serum but not significantly different from that of EDTA-treated serum. There was no difference in cytotoxicity between nafamostat mesylate-treated and untreated, inactivated human serum. The results indicate that the protease inhibitor nafamostat mesylate completely inhibited the complement activation of the immune complex associated with islet cell surface antibody by the classical and alternative pathways.

Animals↗