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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 127 records · Page 7Linked to original sources
PubMed2000

Regulation of cell cycle proteins by TNF-alpha and TGF-beta in cells of oligodendroglial lineage.

Proliferation and apoptosis are two dynamic, interrelated processes that are regulated by growth factors and cytokines. We investigated the effects of tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) on apoptosis and regulation of cell cycle proteins in OLG lineage cells. We found that: (1) both cytokines enhanced apoptosis in neonatal pre-OLGs but only TNFalpha-mediated apoptosis persisted in the presence of a mitogen, fibroblast growth factor (FGF); (2) cell cycle proteins such as p21(waf1/cip1), p27(kip1), cyclin D1 and PCNA were differentially regulated by TNF-alpha and TGF-beta. We conclude that differential modulation of cell cycle proteins by TNF-alpha and TGF-beta contributes to the diversity of their biological effects in OLG lineage cells.

Aging↗
PubMed2000

The effect of SK-896 on post-operative ileus in dogs: gastrointestinal motility pattern and transit.

The aim of this study was to investigate the effect of SK-896 (Phe-Val-Pro-Ile-Phe-Thr-Try-Gly-Glu-Leu-Gln-Arg-Leu-Gln-Glu-Lys-Glu- Arg-Asn-Lys-Gly-Gln-Hse), a new motilin analogue, on gastrointestinal motility and transit in dogs with post-operative ileus, and to compare the effects of this agent on these parameters with the effects of prostaglandin F(2alpha), a well-known gastroprokinetic agent. We used chronically implanted force transducers to measure motility and radiography of radio-opaque markers to measure transit. Infusion of SK-896 1 microgram/kg/h, for 20 min twice a day induced interdigestive migrating contractions-like motility. Infusion of prostaglandin F(2alpha), 20 microgram/kg/h, for 1 h twice a day induced continuous contractions in the distal part of the small intestine. The time of first appearance of interdigestive migrating contractions in the stomach (gastric-interdigestive migrating contractions) and the gastric emptying time of the solid marker with the administration of SK-896 were significantly less than those noted with the administration of prostaglandin F(2alpha). It appears that gastric-interdigestive migrating contractions play an important role in the transit of substances, especially solid substances, in the gastrointestinal tract. We conclude that SK-896, which induced gastric-interdigestive migrating contractions, is effective to induce early recovery from post-operative ileus.

Amino Acid Sequence↗
PubMed2000

Functional anatomical study of psychogenic amnesia.

Psychogenic amnesia is characterized by an inability to recall information already stored in the patient's memory. It is usually related to a stressful or traumatic event that cannot be explained by manifest brain damage. To examine the underlying functional disturbance of brain areas in this condition, we performed a positron emission tomography (PET) activation study on a psychogenic amnesic patient and on 12 normal control subjects. A task requiring explicit retrograde memory of faces was compared with a control task. To assess functional modifications associated with the processes of recovery, a second PET study was performed on the patient 12 months after onset. During the task, activation of the right anterior medial temporal region including the amygdala was increased in the psychogenic amnesic patient. Activation of the bilateral hippocampal regions increased only in the control subjects. During recovery, the right anterior medial temporal region became less active while the right hippocampal region became more active. Activation levels also differed in the anterior cingulate cortex, prefrontal cortex and some other cortical regions between control subjects and the patient. These findings suggest that the changes in these limbic and limbic-cortical functions are related to symptoms of the psychogenic amnesia.

Adult↗
PubMed2000

Effects of oil intake in the conditioned place preference test in mice.

We investigated the effects of corn oil intake in the conditioned place preference (CPP) test in mice. Voluntary intake of corn oil in the light box in the CPP test showed place preference, but its peroral administration 60 min before conditioning did not show either place preference or aversion. Acquisition of the place preference by corn oil intake was blocked by i.p. injection of SCH 23390 (0.03 mg/kg) and haloperidol (0.1 mg/kg), but not by that of (+/-)-sulpiride (100 mg/kg), (-)-sulpiride (100 mg/kg), and L-741, 626 (1 mg/kg) 15 min before conditioning. These results suggest that stimulation of corn oil in the oral cavity, but not its postingestive effects, have positive reinforcing effects and the stimulation of corn oil is at least partly mediated via dopaminergic systems through the D(1) receptors. Moreover, the present results suggest that the CPP test is useful for the study of preferable stimulation and rewarding effects of food intake.

Animals↗
PubMed2000

A multivariate analysis of blood vessel and lymph vessel invasion as predictors of ovarian and lymph node metastases in patients with cervical carcinoma.

BACKGROUND: To the authors' knowledge there are few available data regarding the influence of lymphovascular space invasion, which has been examined separately as two components (lymphatic vessel invasion [LVI] and blood vessel invasion [BVI]), in the metastasis of cervical carcinoma. METHODS: LVI and BVI, which include capillary vessel invasion, were reviewed retrospectively based on the histopathologic slides of 239 women with cervical carcinoma who were treated with radical hysterectomy. The correlation between lymph node and/or ovarian metastases and LVI, BVI, and other histopathologic factors was investigated by multiple logistic regression analysis. The influence of LVI and BVI on survival was examined by Cox regression analysis. RESULTS: The rate of incidence of LVI was higher than that of BVI in all stages of cervical carcinoma (P < 0.0001 for International Federation of Gynecology and Obstetrics Stage IB and Stage II disease and P < 0.05 for Stage III disease). The incidence rate of BVI increased as LVI became more prominent and there was a significant correlation between the two findings (P < 0.0001). BVI was more frequent in adenocarcinoma/adenosquamous carcinoma than in squamous cell carcinoma (P < 0.05). LVI (P < 0.0001) and parametrial invasion (P < 0.0001) were significantly related to lymph node metastasis on multivariate analysis. Conversely, BVI (P < 0.05) and parametrial invasion (P < 0.0025), as well as adenocarcinoma or adenosquamous carcinoma (P < 0.0005), were significantly related to ovarian metastasis on multivariate analysis. With regard to the prognostic significance of these components, it was found that BVI (hazards ratio [HR] = 2.0), ovarian metastasis (HR = 6.5), and lymph node metastasis (HR = 5.5) were significantly related to a poor prognosis in women with cervical carcinoma. CONCLUSIONS: Ovarian metastasis may occur via hematogenous spread of cervical carcinoma. The results of the current study suggest that BVI, including capillary vessels, that is diagnosed separately from LVI using hematoxylin and eosin stained sections may be an important prognostic factor for patients with cervical carcinoma.

Carcinoma, Adenosquamous↗
PubMed2000

Akt/protein kinase B prevents injury-induced motoneuron death and accelerates axonal regeneration.

Motoneurons require neurotrophic factors for their survival and axonal projection during development, as well as nerve regeneration. By using the axotomy-induced neuronal death paradigm and adenovirus-mediated gene transfer, we attempted to gain insight into the functional significances of major growth factor receptor downstream cascades, Ras-extracellular signal-regulated kinase (Ras-ERK) pathway and phosphatidylinositol-3 kinase-Akt (PI3K-Akt) pathway. After neonatal hypoglossal nerve transection, the constitutively active Akt-overexpressing neurons could survive as well as those overexpressing Bcl-2, whereas the constitutively active ERK kinase (MEK)-overexpressing ones failed to survive. A dominant negative Akt experiment demonstrated that inhibition of Akt pathway hastened axotomy-induced neuronal death in the neonate. In addition, the dominant active Akt-overexpressing adult hypoglossal neurons showed accelerated axonal regeneration after axotomy. These results suggest that Akt plays dual roles in motoneuronal survival and nerve regeneration in vivo and that PI3K-Akt pathway is probably more vital in neuronal survival after injury than Ras-ERK pathway.

Animals↗
PubMed2000

ASC1/RAS2 suppresses the growth defect on glycerol caused by the atp1-2 mutation in the yeast Saccharomyces cerevisiae.

To better define the regulatory role of the F(1)-ATPase alpha-subunit in the catalytic cycle of the ATP synthase complex, we isolated suppressors of mutations occurring in ATP1, the gene for the alpha-subunit in Saccharomyces cerevisiae. First, two atp1 mutations (atp1-1 and atp1-2) were characterized that prevent the growth of yeast on non-fermentable carbon sources. Both mutants contained full-length F(1)alpha-subunit proteins in mitochondria, but in lower amounts than that in the parental strain. Both mutants exhibited barely measurable F(1)-ATPase activity. The primary mutations in atp1-1 and atp1-2 were identified as Thr(383) --> Ile and Gly(291) --> Asp, respectively. From recent structural data, position 383 lies within the catalytic site. Position 291 is located near the region affecting subunit-subunit interaction with the F(1)beta-subunit. An unlinked suppressor gene, ASC1 (alpha-subunit complementing) of the atp1-2 mutation (Gly(291) --> Asp) restored the growth defect phenotype on glycerol, but did not suppress either atp1-1 or the deletion mutant Deltaatp1. Sequence analysis revealed that ASC1 was allelic with RAS2, a G-protein growth regulator. The introduction of ASC1/RAS2 into the atp1-2 mutant increased the F(1)-ATPase enzyme activity in this mutant when the transformant was grown on glycerol. The possible mechanisms of ASC1/RAS2 suppression of atp1-2 are discussed; we suggest that RAS2 is part of the regulatory circuit involved in the control of F(1)-ATPase subunit levels in mitochondria.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Comparison of electrocardiographic findings in patients with AL (primary) amyloidosis and in familial amyloid polyneuropathy and anginal pain and their relation to histopathologic findings.

To assess the prevalence of chest pain and ischemic electrocardiographic (ECG) changes and relate them to histopathologic findings of coronary arteries in cardiac amyloidosis, 33 patients with AL (primary) amyloidosis and 60 patients with familial amyloid polyneuropathy (FAP) were examined. Five patients (15%) with AL amyloidosis had recurrent anginal pain with exertion and 2 of them also experienced anginal pain after orthostatic hypotension. The chest pain was associated with transient downsloping or horizontal ST-segment depression with or without T-wave inversion in right precordial leads, whereas the remaining patients with AL amyloidosis and all patients with FAP did not show anginal pain or ischemic ST-T changes. Histologic sections of coronary arteries were obtained in 12 patients with AL amyloidosis, including 4 of the 5 patients who had angina pectaris and in 25 patients with FAP. Three patients with anginal pain had variable degrees of stenoses of the intramural coronary arteries by amyloid deposition predominantly in the media with normal or nearly normal epicardial arteries. One patient with AL amyloidosis who had effort angina showed marked stenosis and complete occlusion of the small coronary vessels by transmural amyloid deposition. The remaining 8 patients with AL amyloidosis and 25 with FAP without chest pain did not exhibit any stenosis or occlusion of both the epicardial and intramural vessels. These findings suggest that ischemic ST-T changes with chest pain are not so rare in patients with AL amyloidosis, and that markedly decreased myocardial oxygen supply due to diffuse stenotic or occlusive disease of the small coronary vessels by amyloid deposition contributes to the development of clinically significant ischemic heart disease in these patients.

Aged↗
PubMed2000

Identification of the novel developmentally regulated gene, Bdm2, which is highly expressed in fetal rat brain.

Most of the neurogenesis take place during the embryonic stage; the genes expressed predominantly in this stage may play important roles in the control of development of the central nervous system. Using a differential display method, we identified the novel rat gene, brain development-related molecule 2 (Bdm2), that is expressed more abundantly in the embryonic brain than in the adult brain. Full-length Bdm2 cDNA consists of 1842 base pairs (bp) and contains an open reading frame of 1260 bp. Northern blot analysis demonstrated that Bdm2 was strongly expressed in the late embryonic brain and was still detected at lower levels in an early postnatal period; in adults, Bdm2 mRNA was decreased to an undetectable level in brain, though the expression of this mRNA was revealed in other tissues. Level of Bdm2 mRNA was maintained during neuronal differentiation of mouse embryonal carcinoma cell P19, but decreased during the differentiation to glial and unidentified non-neuronal cells. In situ hybridization study demonstrated the wide distribution of Bdm2 mRNA in the embryonic brain; in the adult brain, the hybridization signals became more restricted to the hippocampus, olfactory bulb, cerebellum, and neocortex, almost coinciding with the regions where nascent and immature neurons are present. Thus, it appears likely that Bdm2 encodes a protein that is involved in both the regulation of growth of undifferentiated neural cells and the terminal differentiation of neuronal cells.

Amino Acid Sequence↗
PubMed2000

Inactivation of glycogen synthase kinase-3 by protein kinase C delta: implications for regulation of tau phosphorylation.

The role of the phosphatidylinositol 3-kinase (PI3K) pathway in the hyperphosphorylation of tau was investigated in SY5Y human neuroblastoma cells. Wortmannin, an inhibitor of PI3K, induced transient (after 1 h) activation of glycogen synthase kinase-3 (GSK-3), hyperphosphorylation of tau and dose-dependent cytotoxicity. However, continuous inactivation of protein kinase (PK) B was observed from 1 to 24 h, suggesting the involvement of protein kinase(s) other than PKB in the phosphorylation and inactivation of GSK-3 after 3 h. In cells treated with wortmannin, PKC delta fragments were observed, and the PKC activity increased after 3 h, whereas treatment of cells with z-DEVD-fmk, an inhibitor of caspase 3, also inhibited fragmentation of PKC delta and induced continuous activation of GSK-3. It is suggested that fragmentation of PKC delta during the process of apoptosis results in the phosphorylation and inactivation of GSK-3 and consequently inhibition of the phosphorylation of tau.

Alzheimer Disease↗
PubMed2000

Activation of human progelatinase A/promatrix metalloproteinase 2 by Escherichia coli-derived serine proteinase.

Treatment of human uterine cervical fibroblasts with commercial lipopolysaccharide (LPS) preparations from different serotypes of Escherichia coli effectively augmented the processing of mammalian progelatinase A/promatrix metalloproteinase (proMMP)-2 to a 62-kDa form of MMP-2. When purified proMMP-2 was incubated with LPS preparations, the proenzyme was similarly processed into the 62-kDa active MMP-2 in a time- and dose-dependent manner. By contrast, progelatinase B/proMMP-9 and prostromelysin 1/proMMP-3 were not activated. A serine proteinase inhibitor, phenylmethylsulfonyl fluoride, completely interfered with this LPS-mediated activation of proMMP-2. This is novel evidence that E. coli serine proteinase is a specific activator of proMMP-2. Thus, it is very likely that E. coli infection plays a crucial role in the degradation of connective tissues via the activation of proMMP-2, and the resultant active MMP-2 participates in the dysfunction of connective tissues such as in the preterm rupture of fetal membranes.

Animals↗
PubMed2000

Apoptosis in cultured midgut cells from heliothis virescens larvae exposed to various conditions.

We exposed midgut cells from primary cultures of Heliothis virescens larvae to cell-free previously used medium, the Vaughn X and HyQ SFtrade mark media used for serum-free culture of insect cell lines which do not support H. virescens midgut cells, and to toxin from Bacillus thuringiensis. A statistically significant increase in the percent of dying cells was counted in cell populations in Vaughn X medium. Use of the TUNEL method to detect apoptosis indicated a low rate (7.2%) of apoptosis in control cultures grown in Heliothis medium, an increase to approximately 20% in previously used and HyQ SFtrade mark media, and to approximately 45% of cells remaining after exposure to and initial destruction by B. thuringiensis toxin. Apoptotic nuclei were predominant (approximately 6%) in mature columnar cells in control cultures. Approximately 1% of goblet, stem, and differentiating cells were apoptotic. However, apoptosis rose to 12% in stem and differentiating cells exposed to used and unsuitable medium. B. thuringiensis exposure to toxin for 2-3 days resulted in visible membrane damage and necrosis, causing the death of 84% of the cells as measured by both the TUNEL and Annexin methods. Some of the columnar cells and stem and differentiating cells that remained also contained apoptotic nuclei. Stem and differentiating cells normally replace dying mature cells in the midgut. Thus, exposure of cultures of H. virescens midgut cells to adverse environments such as unsuitable or poisonous media appeared to induce down-regulation of the cell populations by apoptosis.

Animals↗
PubMed2000

Cloning of vitellogenin cDNA of the American cockroach, Periplaneta americana (Dictyoptera), and its structural and expression analyses.

A cDNA expression library constructed from poly (A)(+) RNA prepared from vitellogenic female fat body cells of the American cockroach, Periplaneta americana (Dictyoptera) was screened using a polyclonal antiserum against the 100-kD polypeptide(s) from the egg extract. A partial Vg cDNA clone was obtained and sequenced. The 5' end portion of the cDNA was then obtained by the RACE method, cloned, and sequenced. The combined complete Vg cDNA was 5,854 bp long and contained a single ORF encoding 1,896 amino acids. The entire deduced amino acid sequence was aligned confidently with those of the known insect Vgs. A GL/ICG motif, a number of cysteines at conserved locations following this motif, and a DGXR motif upstream of the GL/ICG motif were present near the C-terminal. The chemically determined N-terminal amino acid sequence of the 170-kD polypeptide from the egg extract completely matched the deduced sequence starting from just after one of the consensus (RXXR) cleavage sites, indicating the occurrence of post-translational cleavage in the fat body cells. The Vg gene begins to be expressed in the 2-day-old adult female fat body cells but is never expressed in ovaries or in male fat body cells. Hemolymph Vg was first detected by immunoblotting in 4-day-old adult females, 2 days after the beginning of gene expression. Western blot analysis of major yolk polypeptides in nine cockroach species belonging to the two superfamilies, Blattoidea and Blaberoidea, using the antisera against P. americana major yolk polypeptides showed that the similarities in Vn antigenicity are basically limited to within a superfamily.

Amino Acid Sequence↗
PubMed2000

Off-pump coronary artery bypass grafting via partial sternotomy. An alternative to left anterior small thoracotomy.

Four patients, who were considered to be inappropriate candidates for left anterior small thoracotomy, underwent off-pump coronary artery bypass grafting via partial sternotomy. Under a median skin incision over the lower half of the sternum, the sternum below the second rib was cut in an "inverted L" (or "C") shape. Without cardiopulmonary bypass, the left internal thoracic artery was anastomosed to the left anterior descending artery in all patients, and a saphenous vein graft was anastomosed to the right coronary artery in one of them. Partial sternotomy has some advantages as an alternative to left anterior small thoracotomy, in that it enables multiple-bypass grafting without cardiopulmonary bypass and conversion to cardiopulmonary bypass, should it be come necessary, would be relatively uncomplicated.

Aged↗
PubMed2000

Partial sternotomy ("C" incision) as standard access for full range of adult cardiac operations.

OBJECTIVE: In our institute, partial sternotomy has been adopted for standard access in the full range of adult cardiac operations, including coronary artery bypass grafting. In this study, our clinical experience is reviewed. METHODS: Since April 1998, of 100 cardiac surgical patients, 64 underwent partial sternotomy, while 36 patients had the traditional full sternotomy because of high surgical risk factors or anatomical reasons. Most of the patients having minimal access had a "C" incision, that is, a left lower partial sternotomy. RESULTS: The procedures performed with the "C" incision were coronary artery bypass grafting, valve surgery, aortic root replacement, closure of atrial septal defect, and so on. There were two hospital deaths after partial sternotomy. Compared with full sternotomy patients, partial sternotomy patients had a shorter hospital stay, while their bypass times were longer. Their skin incisions were 11.7 cm on average. CONCLUSION: The "C" incision can provide satisfying results and can serve as the standard approach in the full range of cardiac operations.

Adult↗
PubMed2000

Change in mechanical receptive field properties induced by GABA(A) receptor activation in the trigeminal spinal nucleus caudalis neurons in rats.

The purpose of the present study was to characterize the effect of a local GABAergic inhibitory mechanism on the mechanical receptive field properties of trigeminal spinal nucleus caudalis (SpVc) neurons by iontophoretic application of a gamma-aminobutyric acidA (GABA(A))-antagonist and -agonist. A total of 24 SpVc neurons that responded to orofacial mechanical stimulation were extracellularly recorded by means of multibarrel microelectrodes in urethane-anesthetized rats. The GABA(A) antagonist bicuculline (30 nA, 5 min) enhanced the activities of SpVc neurons (20/24) induced by both touch/pressure and pinch stimuli and also lowered the mechanical stimulation threshold (touch/pressure). Spontaneous discharges in these neurons (20/24) were significantly increased after bicuculline application. Eighteen out of 24 SpVc neurons showed signs of expansion of the receptive field size after iontophoretic application of bicuculline. These changes showed a current-dependent manner and were reversed in approximately 15-20 min. Iontophoretic application of the GABA(A) agonist muscimol induced a current-related inhibition of neuronal activity elicited by touch/pressure and pinch stimuli as well as a decrease in the size of receptive fields. The facilitation of evoked responses and receptive field expansion of SpVc neuron induced by bicuculline application were blocked by coapplication of muscimol (50 nA, 5 min). These results suggest that a local mechanism acting via GABA(A) receptors normally exerts a tonic inhibition of mechanoreceptive transmission in the trigeminal spinal nucleus neurons and this effect may limit responsiveness and size of receptive fields.

Animals↗
PubMed2000

Induction of apoptosis by colchicine in taste bud and epithelial cells of the mouse circumvallate papillae.

Apoptotic cells in the taste buds and epithelia of mouse circumvallate papillae after colchicine treatment were examined by the methods of in situ DNA nick-end labeling, immunocytochemistry, and electron microscopy. After colchicine treatment, numerous positive cells appeared in the taste buds by DNA nick-end labeling, and some epithelial cells in the basal and suprabasal layers in and around the circumvallate papillae also revealed positive staining. Condensed and fragmented nuclei with a high density were occasionally found in the taste bud cells and in the basal and suprabasal layer epithelial cells by electron-microscopic observation. An immunocytochemical reaction for tubulin revealed weak staining in taste bud cells, because of the depolymerization of microtubules, and a decrease of the microtubules in the taste bud cells was observed by electron microscopy. These results indicate that colchicine treatment of mice induces the apoptosis of taste bud and epithelial cells in the circumvallate papillae and dorsal epithelial cells around the circumvallate papillae.

Animals↗