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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 217 records · Page 12Linked to original sources
PubMed1999

Medial prefrontal cortex generates frontal midline theta rhythm.

Frontal midline theta rhythm (Fm theta) is a distinct theta activity of EEG in the frontal midline area that appears during concentrated performance of mental tasks in normal subjects and reflects focused attentional processing. To tomographically visualize the source current density distributions of Fm theta, we recorded Fm theta by using a 64-channel whole-head MEG system from four healthy subjects, and applied a new analysis method, synthetic aperture magnetometry (SAM), an adaptive beam forming method. Fm theta was observed in the MEG signals over the bilateral frontal regions. SAM analysis showed bilateral medial prefrontal cortices, including anterior cingulate cortex, as the source of Fm theta. This result suggests that focused attention is mainly related to medial prefrontal cortex.

Adult↗
PubMed1999

Evidence that a phosphatidylinositol 3,4,5-trisphosphate-binding protein can function in nucleus.

PIP3BP is a phosphatidylinositol 3,4,5-trisphosphate-binding protein (PIP3BP) abundant in brain, containing a zinc finger motif and two pleckstrin homology (PH) domains. Staining of rat brain cells with anti-PIP3BP antibody and determination of localization of PIP3BP fused to the green fluorescent protein (GFP-PIP3BP) revealed that PIP3BP was targeted to the nucleus. Targeting was dependent on a putative nuclear localization signal in PIP3BP. Generation of PIP3 in the nucleus was detected in H2O2-treated 293T cells, nerve growth factor (NGF)-treated PC12 cells, and platelet-derived growth factor (PDGF)-treated NIH 3T3 cells. Translocation of phosphatidylinositol 3-kinase (PI 3-kinase) to the nucleus and enhanced activity of PI 3-kinase in the nucleus fraction were observed after H2O2 treatment of 293T cells, suggesting that PI 3-kinase can be activated in the nucleus as well as in the membrane after appropriate stimulation of the cells. Co-expression of the constitutively active PI 3-kinase with PIP3BP resulted in exportation of the protein from the nucleus to the cytoplasm, suggesting that PIP3BP can function as a PIP3-binding protein in the intact cells. These results imply that there may be an unknown function of PI 3-kinase in the nucleus.

3T3 Cells↗
PubMed1999

The three copies of the ATP1 gene are arranged in tandem on chromosome II of Saccharomyces cerevisiae S288C.

In the yeast Saccharomyces cerevisiae there are three copies of the F(1)F(0)-ATPase alpha-subunit gene ATP1 on chromosome II (Takeda et al., 1995). However, after genome analysis using S. cerevisiae strain S288C, only one ATP1 gene sequence was observed (Feldman et al., 1994; Obermaier et al., 1995). To check whether the number of copies of ATP1 is strain-dependent or not, we carried out three different experiments: (a) long-PCR analyses of total DNAs isolated from several reference strains, carried out by preparing 29-mer oligonucleotides based on the 5'- and 3'- up- and downstream regions of the ATP1 nucleotide sequence using the data from the genome project to synthesize primers; (b) restriction analyses of chromosome II from the reference strains with SplI; and (c) long-PCR analyses of prime clones 70113 and 70804, both of which contained two ATP1 gene copies, ATP1a and ATP1b, and ATP1b and ATP1c, respectively, using 30 nucleotides just inside the 3'-end (sense) and 5'-end (antisense) of the ATP1-coding region as primers. In the case of the long-PCR experiments, the reference strains DC5, SEY2102, W303-1A, W303-1B, LL20 and DBY746, as well as strain S288C, generated a DNA fragment of approximately 32 kb, which hybridized with ATP1. During SplI digestion, a DNA fragment of more than 50 kb which hybridized with ATP1, was obtained from all reference strains. In the case of prime clone analyses using the long-PCR experiments, the distance between ATP1a and ATP1b or ATP1b and ATP1c was approximately 10 kb or 7 kb, respectively. The S288C strain generated these two DNA fragments, as do the other strains. These results showed that all these strains contained three copies of ATP1 on chromosome II.

Base Sequence↗
PubMed1999

Cytopathological observations in a 27-year-old female patient with endometrioid adenocarcinoma arising in the lower uterine segment of the uterus.

The determination of the malignancy of an endometrioid adenocarcinoma arising in the lower uterine segment (LUS) is difficult because of the high degree of differentiation of adenocarcinoma. The cytopathological and immunohistochemical features of endometrioid adenocarcinoma arising in the LUS of a young adult female are presented. The preoperative cytopathological examination of a 27-yr-old female could not enable an accurate diagnosis of malignancy. Hysterectomy specimens revealed the presence of an endometrioid-type adenocarcinoma with minimal atypia and myometrial invasion, which was located in the LUS. This tumor was consistent with a histological diagnosis of endometrioid minimal-deviation adenocarcinoma (MDA). Immunohistochemically, the tumor's glands were p53-, proliferating cell nuclear antigen-, and carcinoembryonic antigen-positive, and estrogen receptor-, progesterone receptor-,and vimentin-negative. The cytological and surgical specimens showed a remarkable association of squamous metaplasia. Although cytopathological difficulties in determining malignancy of MDA endometrioid adenocarcinoma arising in the LUS are well-known, the following features worth noting include: 1) squamous metaplasia on cytological and histological slides; 2) epithelial cells incorporating polymorphic nuclear neutrophils on cytological slides; and 3) positive immunohistochemistry of p53 protein. Diagn. Cytopathol. 1999;21:117-121.

Adult↗
PubMed1999

Relationship between autofluorescence and advanced glycation end products in diabetic lenses.

Autofluorescence and advanced glycation end product (AGE) levels were measured in the lenses of 9 diabetic Chinese hamsters and 6 age-matched controls. Lens autofluorescence also was measured in 37 diabetic patients and 14 age-matched controls. Lens autofluorescence values were measured noninvasively with a lens measurement system using color filters with peak transmission at 365- and 434-nm wavelengths (excitation and emission, respectively) that are characteristic of AGE fluorescence. The peak lens autofluorescence level was used as the lens autofluorescence value, and the mean lens autofluorescence values from both eyes of each subject were used for statistical analysis. The AGE levels in one lens from each hamster were measured by noncompetitive enzyme-linked immunosorbent assay with a polyclonal anti-AGE antibody. We found a 2.2 times increase of the mean lens autofluorescence value of diabetic hamsters in comparison with that of controls (P<0.01). We also found a 1.5 times increase of the mean AGE level from the lenses of diabetic hamsters in comparison with that of controls (P<0.01). Moreover, a statistically significant positive correlation between the AGE level and autofluorescence value in the same lenses was observed in all hamsters (rho=0.58, P<0.05). In human subjects, we found a 1.4 times increase of the mean lens autofluorescence value of diabetic patients in comparison with that of age-matched controls (P<0.01). Our results suggest that non invasive measurement of lens autofluorescence may be a guide to AGE levels in lenses.

Aged↗
PubMed1999

The effect of flow on the neutrophil-mediated Ca2+ responses in human vascular endothelial cells stimulated by endotoxin.

Leukocyte-vascular endothelial cell (EC) interactions which promote inflammatory and immune reactions involve bidirectional signaling between two cell types. We investigated the effects of flow on neutrophil-mediated changes in endothelial intracellular Ca2+ levels ([Ca2+]i). Cultured human umbilical vein ECs stimulated by endotoxin were labeled with Fura-2 and exposed to fluid flow with neutrophils. The individual changes in [Ca2+]i were monitored. The application of flow with neutrophils to stimulated ECs led to an increase in [Ca2+]i although either flow without neutrophils or neutrophils without flow rarely induced a rise in [Ca2+]i. Furthermore, flow application with neutrophils to unstimulated ECs also rarely promoted a rise in [Ca2+]i. These findings suggest that the flow might thus induce or enhance the inflammatory process by the induction of Ca2+ signaling in endotoxin-stimulated endothelium facing neutrophils in the blood flow.

Calcium↗
PubMed1999

Long-term results of the fenestrated Fontan operation. Progress of patients with patent fenestrations.

The fenestrated Fontan operation was introduced as a modification of the "completed" Fontan operation for patients with high risk factors, and low operative mortality has frequently been reported. However, use of the umbrella device is now restricted, and this procedure should be performed without subsequent closure. In this paper, we review our clinical experience with this procedure and discuss ongoing problems. Sixteen patients (4 tricuspid atresia and 12 other cardiac anomalies including 5 cases of univentricular heart) underwent the fenestrated Fontan operation (7 atriopulmonary and 9 total cavopulmonary connection). All of them have some risk factors for a completed Fontan operation. There were three early deaths of the 16. Two experienced an anticipated thromboembolic accident, one of which involved the pulmonary aspect while the other involved the arterial aspect. Patients who survived the operation have progressed well and have a clinical status of New York Heart Association class I, with the exception of one late death due to congestive heart failure. There have been no thromboembolic accidents in this group during the late follow-up period. Spontaneous closures of the fenestrations were noted in two patients. The late mean Qp/Qs value in patients with patent fenestrations was 0.80 +/- 0.1, SaO2 was 88.8 +/- 5.6%, and right atrial pressure was 9.7 +/- 3.8 mmHg. No major problems have been encountered in patients with a patent fenestration over extended periods. A modified Fontan operation to fit a permanently open fenestration may be considered as a final surgical option for certain high-risk patients.

Adolescent↗
PubMed1999

Effects of electrical stimulation of the tooth pulp and phrenic nerve fibers on C1 spinal neurons in the rat.

Effects of electrical stimulation of the ipsilateral tooth pulp (TP) on C1 spinal neurons were determined in 33 anesthetized rats. One hundred and seven neurons responded to TP stimulation. In 10 rats, the activity of 18 C1 spinal neurons and the amplitude of a digastric electromyogram (dEMG, n = 10) increased proportionally during the TP stimulation at an intensity of 1-3 times the threshold for jaw-opening reflex (JOR). Excitatory receptive somatic fields were examined in 61 neurons. Somatic field locations of many neurons (67.2%) involved the ipsilateral face, neck, and jaw. The activity of 45 neurons was increased by both noxious pinch and brushing hair. Of the 107 C1 spinal neurons responding to TP stimulation, 55 were tested to determine the effects of electrical stimulation of the ipsilateral phrenic nerve (PN) above the heart. Twenty-eight of 55 neurons tested were excited; no change in activity was seen for the remaining 27 neurons. The activity of six neurons increased as the intensity of PN stimulation was increased. Excitatory receptive somatic fields were determined in 28 neurons, and somatic field locations of 17 neurons (60.7%) included the ipsilateral face, neck, and jaw. Both noxious pinch and brushing hair excited all 28 neurons. These results suggest that there may be the convergence of face, neck, jaw, TP, and PN afferents on the same C1 spinal neurons in the rat.

Animals↗
PubMed1999

Effects of N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists on excitation of the tooth-pulp-evoked C1 spinal neurons in the rat.

To examine whether there is a difference between the effects of iontophoretically applied N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists on the activity of C1 spinal neurons with input from the tooth pulp, extracellular single recordings were performed in pentobarbital-anesthetized rats. The activity of 16 C1 spinal neurons and the amplitude of the digastric electromyogram increased proportionally by 1.0-3.5 times the threshold for jaw-opening reflex. After iontophoretic application (10, 30 and 50 nA, 5 min) of NMDA receptor blocker (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a, d]cycloheptene-5,10-imine hydrogen maleate or non-NMDA receptor blocker (6-cyano- 7-nitroquinoxaline-2,3-dione), the mean number of spikes responding to the tooth pulp stimulation at x3.5 threshold for jaw-opening reflex was significantly decreased. Under these conditions, there were no significant differences between the amplitudes of the dEMG before and after applications of both NMDA and non-NMDA receptor antagonists. These results suggest that the release of endogenous excitatory neurotransmitters is necessary for activation of C1 spinal neurons that are associated with the transmission of nociceptive information, and that both NMDA and non-NMDA receptors contribute to the mechanism of excitation of tooth-pulp-evoked C1 spinal neurons.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1999

Ultrastructure of rat duodenal myenteric plexus revealed by quick-freezing and deep-etching method.

A quick-freezing and deep-etching (QF-DE) method was employed with whole-mount strips of rat duodenal muscle walls to exhibit the cytoskeletons of the myenteric plexus. Nerve fibers in the myenteric plexus, which contained fewer neurofilaments than other types of neurons examined, had many varicosed contours, and were bundled by enteroglial cells. Cytoskeleton arrays were rarely observed in the varicosed regions, where synaptic vesicles were often seen, although other nerve regions contained many neurofilaments running almost in parallel with the nerve fiber bundle. Enteroglial cells had short cytoskeletons predominantly across the cytoplasm, becoming thinner the around varicosed regions of the nerve bundles. Such enteroglial extruded areas were often in close association with neighboring nerve fibers, indicating intercommunications between the nerve fibers. In distal parts of enteric nerve processes, there were numerous synaptic vesicles, but few neurofilaments. Smooth muscle cells were closely associated with the enteric nerve processes. Fine network structures, responsible for the extracellular matrix, were present between the smooth muscle cells and the enteric nerve processes. These specific structures of the myenteric plexus could be important for signalling or for the transportation of neurotransmitters involved in gut motility.

Animals↗
PubMed1999

Extended aortic replacement in acute dissection by the separated elephant trunk technique.

BACKGROUND: Extensive aortic replacement in acute dissection is currently not a widely accepted method of treatment. METHODS: We developed a safe method for extended aortic repair including the aortic arch in type A acute dissection, and describe here its application in 5 cases. This method was based on a modification of the elephant trunk method and several other strategies. Most of the procedures were carried out under simple hypothermic circulatory arrest. RESULTS: All patients recovered within 2 days without recurrent nerve injury. One patient suffered from unilateral upper arm palsy due to severe innominate dissection. Patients were all discharged and early postoperative computed tomography (CT) showed thrombotic obliteration around the elephant trunk. Follow-up CT after 4 to 18 months confirmed that thromboexclusion proceeded down to the distal end of the elephant graft in 1 patient and to the diaphragmatic level in 3 patients. Total obliteration was observed in the remaining 1 patient. CONCLUSIONS: This technique enables extended aortic repair in acute dissection with no increase in morbidity, and effectively promotes thromboexclusion of the dissected lumen to a wider extent than conventional methods.

Aged↗
PubMed1999

Immunofluorescence detection of cadherins in mouse tooth germs during root development.

The distribution of two cell-adhesion molecules, E- and P-cadherin, was studied in relation to morphological changes in Hertwig's epithelial root sheath Before root dentinogenesis had started, the root sheath expressed both cadherins. As dentinogenesis proceeded, the sheath fragmented and lost P-cadherin rapidly and E-cadherin slowly, whereas the intact sheath at the apical end continued to express both. These results suggest that the two cadherins play a part in root as well as in crown development, and indicate that the decrease in the amount of these molecules and the fragmentation of the epithelial root sheath are interrelated.

Animals↗
PubMed1999

Presenilin-2 mutation and polymorphism in Japanese Alzheimer disease patients.

The Asn141Ile mutation of the presenilin 2 gene is responsible for familial early-onset Alzheimer disease found in Volga-German kindreds. However, the genetic influence of presenilin 2 gene on sporadic Alzheimer disease remains unknown. In this study, the frequency of the mutation and genetic association with the presenilin 2 locus were investigated in Japanese sporadic cases. The Asn141Ile mutation was not found in 88 cases of sporadic Alzheimer disease or 13 unrelated cases of familial Alzheimer disease. Fifty cases of late onset sporadic Alzheimer disease and 50 age-matched controls indicated no association with an exon 3 polymorphism of the presenilin 2 gene. These results indicate that the presenilin 2 mutation is not a major cause of Alzheimer disease.

Age of Onset↗
PubMed1999

Dextran sulfate inhibits E-selectin-mediated neutrophil adhesion to endotoxin-activated vascular endothelial cells.

Effects of heparin-like glycosaminoglycans (h-GAGs) on neutrophil adhesion to endothelial cells (ECs) were investigated under physiological flow conditions using human umbilical vein ECs. Neutrophil adhesion to lipopolysaccharide-activated ECs was assayed under rotating conditions with addition of h-GAGs or monoclonal antibodies (mAbs) against selectins. Neutrophil adhesion to activated ECs under rotating conditions was suppressed completely by anti-E-selectin mAb and partially by anti-L-selectin mAb. Addition of dextran sulfate or heparin also significantly inhibited neutrophil adhesion to ECs under the same conditions. Moreover, effects of h-GAGs on neutrophil adhesion to recombinant E-selectin-coated plates were analyzed. Anti-E-selectin mAb and dextran sulfate, but not heparin, significantly inhibited neutrophil adhesion to E-selectin-coated plates. Results suggest that dextran sulfate inhibited E-selectin-mediated neutrophil adhesion to endotoxin-activated ECs under physiologic flow conditions.

Antibodies, Monoclonal↗
PubMed1999

In vivo imaging of spontaneous ultraweak photon emission from a rat's brain correlated with cerebral energy metabolism and oxidative stress.

Living cells spontaneously emit ultraweak light during the process of metabolic reactions associated with the physiological state. The first demonstration of two-dimensional in vivo imaging of ultraweak photon emission from a rat's brain, using a highly sensitive photon counting apparatus, is reported in this paper. It was found that the emission intensity correlates with the electroencephalographic activity that was measured on the cortical surface and this intensity is associated with the cerebral blood flow and hyperoxia. To clarify the mechanism of photon emission, intensity changes from whole brain slices were examined under various conditions. The removal of glucose from the incubation medium suppressed the photon emission, and adding 50 mM potassium ions led to temporal enhancement of emission and subsequent depression. Rotenone (20 microM), an inhibitor of the mitochondrial electron transport chain, increased photon emission, indicating electron leakage from the respiratory chain. These results suggest that the photon emission from the brain slices originates from the energy metabolism of the inner mitochondrial respiratory chain through the production of reactive oxygen. Imaging of ultraweak photon emission from a brain constitutes a novel method, with the potential to extract pathophysiological information associated with neural metabolism and oxidative dysfunction of the neural cells.

Animals↗
PubMed1999

Effects of the antihypertensive drug nifedipine on albuminuria and renal histopathology in young spontaneously hypertensive rats with diabetes.

We investigated the renal protective effect of nifedipine (2-nitrophenyl derivative BAY a 1040) in streptozotocin (STZ)-induced spontaneously hypertensive rats (SHRs, 8 weeks of age). Diabetic SHRs were treated with 40 mg/kg/day of nifedipine or efonidipine as controls for 16 weeks. Dosage of nifedipine or efonidipine was chosen after preliminary studies demonstrated that it showed moderate antihypertensive action (more than a 20% decrease in systemic blood pressure after treatment). In the diabetic SHR, the excretion of urinary albumin was increased and reached 4.41 +/- 0.08 mg/day at 24 weeks. The levels of urinary albumin in the diabetic SHR after treatment with nifedipine were significantly less than those in the diabetic SHR at 24 weeks (p < 0.01). Levels of the ratio of creatinine clearance to body weight were significantly decreased in the diabetic SHR after treatment with nifedipine. In light microscopy, the ratio of glomerular tufts to Bowman's areas was significantly decreased compared with those in the diabetic SHRs (p < 0.05). These findings suggest that nifedipine inhibits the development of albuminuria and glomerular enlargement in STZ-induced diabetic SHRs. There was no significant difference in the changes in antihypertensive or antialbuminuric effects between nifedipine and efonidipine. Thus, nifedipine, as well as efonidipine, may become a useful antihypertensive drug with a renal protective effect.

Albuminuria↗
PubMed1999

Regional distribution of presenilin-1 messenger RNA in the embryonic rat brain: comparison with beta-amyloid precursor protein messenger RNA localization.

The messenger RNA expression of presenilin-1, an important gene responsible for early-onset familial Alzheimer's disease, was investigated in the embryonic rat brain with in situ hybridization histochemistry using an oligonucleotide probe specific to the messenger RNA. It was also compared with that of beta-amyloid precursor protein messenger RNA. Presenilin-1 and beta-amyloid precursor protein messenger RNA were abundantly expressed throughout the central nervous system in the embryonic day 13, 17 and 20 rat brain. Presenilin-1 messenger RNA was strongly expressed in both neuroepithelium and differentiating fields. In contrast, beta-amyloid precursor protein messenger RNA was preferentially expressed in differentiating fields, while low expression of beta-amyloid precursor protein messenger RNA was seen in neuroepithelium. Although the expression patterns of these two messenger RNAs were basically similar, there seemed to be a tendency that presenilin-1 messenger RNA was preferentially expressed in immature neurons, while beta-amyloid precursor protein messenger RNA was preferentially expressed in mature neurons, suggesting that presenilin-1 is expressed earlier than beta-amyloid precursor protein and that presenilin-1 is involved in beta-amyloid precursor protein processing. These data raise the possibility that presenilin-1 and beta-amyloid precursor protein co-operatively play pivotal roles in rat neurogenesis.

Amyloid beta-Protein Precursor↗