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Y Nakagami

Publications and source records attributed to Y Nakagami.

At least 19 recordsLinked to original sources
PubMed2004

Observation of magnetic multilayers by electron holography.

Magnetic structures of Co/Cu multilayers in cross section are observed by two kinds of electron holography: a Fourier method and a phase-shifting method, which is introduced briefly. The Fourier method can easily reconstruct wave functions and is applied to many specimens, whereas the phase-shifting method requires longer time for processing, but has a higher spatial resolution that permits us to discuss fine structures. Magnetization vectors in Co layers aligning parallel and separating into two blocks with antiparallel alignment are observed. Magnetic blurring on the boundary between Co and Cu in the reconstructed phase images is larger than the estimated atomic roughness.

Cobalt↗
PubMed2002

Correlation between major histocompatibility complex class I molecules and CD8+ T lymphocytes in prostate, and quantification of CD8 and interferon-gamma mRNA in prostate tissue specimens.

OBJECTIVE: To investigate the immunology of host-tumour interaction, critical for the development of immunotherapy against cancers, by assessing the major histocompatibility complex (MHC) class I expression in both benign and malignant prostate disease, and the relationship between their expression and degree of tumour-infiltrating lymphocytes. MATERIALS AND METHODS: Direct serial analysis of gene expression in tumours is an extremely sensitive and powerful tool for monitoring immunological changes in the immunotherapy of solid tumours. Most previous monitoring protocols rely mainly on the analysis of patient's peripheral blood but in the present study the direct molecular analysis of small tissue samples was used, and its accuracy compared with that of conventional immunohistochemical analysis. Twenty-four formalin-fixed, paraffin-embedded prostate samples (11 benign and 13 carcinoma) were used for the immunohistochemical analysis of CD8+ T lymphocytes and MHC class I expression. CD8+ T lymphocytes were counted using an ocular grid and MHC class I measured using digital image-analysis software. Twenty-seven frozen prostate tissue samples (12 benign and 15 carcinoma) were used for direct gene measurements of CD8 and interferon-gamma using a quantitative real-time polymerase chain reaction. RESULTS: There were significantly fewer CD8+ T lymphocytes in prostate carcinoma nests than in benign prostate. There was a significant correlation between the number of CD8+ T lymphocytes and MHC class I expression in the prostate. There was a strong correlation between the immunohistochemical estimates of CD8+ T lymphocytes and CD8 gene by polymerase chain reaction, but no significant difference between benign prostate and prostate carcinoma tissue in gene measurements. CONCLUSION: Down-regulation of MHC class I expression by prostate cancer cells is associated with fewer CD8+ T lymphocytes and hence might be important in cancer growth. In addition, the measurement of gene expression in small tissue samples might be useful for monitoring the efficacy of treatment throughout cancer therapy.

Aged↗
PubMed2001

An occurrence of salmonella infection in cranes at the Izumi Plains, Japan.

Ten thousand or more cranes migrate from Siberia and stay at the Izumi Plains, in the northern part of Kagoshima prefecture, Japan, every winter season. Four hundred and twenty samples of cranes feces were obtained 1995 to 1997 and investigated for Salmonella. As a result, twenty-nine of Salmonella strains were isolated. All isolates were determined to be identical, Salmonella Typhimurium (04:i: 1,2). since all of them indicated the same patterns of plasmid profiling and antibiotic sensitive spectrums. The isolates showed a high pathogenicity to chicken, and most of them were isolated in the latter half of the winter season; therefore the cranes were infected with the isolates during the winter season.

Animals↗
PubMed2000

Meltrin alpha cytoplasmic domain interacts with SH3 domains of Src and Grb2 and is phosphorylated by v-Src.

Meltrin alpha/ADAM12 is a member of the ADAM/MDC family proteins characterized by the presence of metalloprotease and disintegrin domains. This protein also contains a single transmembrane domain and a relatively long cytoplasmic domain containing several proline-rich sequences. These sequences are compatible with the consensus sequences for binding the Src homology 3 (SH3) domains. To determine whether the proline-rich sequences interact with SH3 domains in several proteins, binding of recombinant SH3 domains to the meltrin alpha cytoplasmic domain was analysed by pull-down assays. The SH3 domains of Src and Yes bound strongly, but that of Abl or phosphatidylinositol 3-kinase p85 subunit did not. Full-length Grb2/Ash bound strongly, whereas its N-terminal SH3 domain alone did less strongly. Src and Grb2 in bovine brain extracts also bound to meltrin alpha cytoplasmic domain on affinity resin. Furthermore, immunoprecipitation with a monoclonal antibody to meltrin alpha resulted in coprecipitation of Src and Grb2 with meltrin alpha in cell extracts, suggesting that Src and Grb2 are associated in vivo with meltrin alpha cytoplasmic domain. This notion was also supported by the findings that exogenously expressed meltrin cytoplasmic domain coexisted with Src and Grb2 on the membrane ruffles. The C-terminal Tyr901 of meltrin alpha was phosphorylated both in vitro and in cultured cells by v-Src. These results may imply that meltrin alpha cytoplasmic domain is involved in a signal transduction for some biological function through the interaction with SH3-containing proteins.

ADAM Proteins↗
PubMed2000

Laminin degradation by plasmin regulates long-term potentiation.

Plasmin is converted from its zymogen plasminogen by tissue type or urokinase type plasminogen activator (PA) and degrades many components of the extracellular matrix (ECM). To explore the possibility that the PA-plasmin system regulates synaptic plasticity, we investigated the effect of plasmin on degradation of ECM and synaptic plasticity by using organotypic hippocampal cultures. High-frequency stimulation produced long-term potentiation (LTP) in control slices, whereas the potentiation was induced but not maintained in slices pretreated with 100 nM plasmin for 6 hr. The baseline synaptic responses were not affected by pretreatment with plasmin. The impairment of LTP maintenance was not observed in slices pretreated with 100 nM plasmin for 6 hr, washed, and then cultured for 24-48 hr in the absence of plasmin. To identify substrates of plasmin, the expression of three major components of ECM, laminin, fibronectin, and type IV collagen, was investigated by immunofluorescence imaging. The three ECM components were widely distributed in the hippocampus, and only laminin was degraded by plasmin pretreatment. The expression level of laminin returned to normal levels when the slices were cultured for 24-48 hr after washout of plasmin. Furthermore, preincubation with anti-laminin antibodies prevented both the degradation of laminin and the impairment of LTP maintenance by plasmin. These results suggest that the laminin-mediated cell-ECM interaction may be necessary for the maintenance of LTP.

Animals↗
PubMed2000

Endogenous meltrin alpha is ubiquitously expressed and associated with the plasma membrane but exogenous meltrin alpha is retained in the endoplasmic reticulum.

Meltrin alpha (ADAM12) is a member of the ADAM (MDC) protein family characterized by the presence of metalloprotease and disintegrin domains. ADAM proteins contain single transmembrane domains, and the processed mature proteins are postulated to span the plasma membrane. It has been reported that transfection of a truncated meltrin alpha cDNA lacking the prodomain and metalloprotease domain promotes skeletal muscle cell fusion. We show here that meltrin alpha was constitutively expressed in both undifferentiated and differentiated C2 skeletal muscle cells and also in fibroblasts. Both its precursor and processed mature forms were present in these cells. Thus, meltrin alpha may play general roles in addition to its roles in myogenesis. Since endogenous meltrin alpha cannot be detected by immunofluorescence microscopy, we examined the location of the exogenously expressed protein by transfection. Unexpectedly, the exogenously expressed meltrin alpha was located to a network structure of the endoplasmic reticulum (ER) but not to the plasma membrane. Cell fractionation revealed that the intrinsic mature protein was associated with the plasma membrane. However, the exogenously expressed protein remained unprocessed. These results seem to imply that the exogenously expressed meltrin alpha is not translocated from the ER to the trans-Golgi network, where a processing enzyme resides, and that it is consequently not converted to the mature form. Thus, the transfected meltrin alpha is unlikely to exert its physiological functions. Conversely, the ER may serve as a reservoir of the latent form of intrinsic meltrin alpha.

ADAM Proteins↗
PubMed1999

Kynurenine concentration of serum was increased by exercise.

Kynurenine pathway of tryptophan makes a lot of physiological active substances, such as quinolinate, NAD and so on, suggesting that kynurenine itself may play a very important role physiologically. Therefore, we examined the influence of exercise on serum kynurenine concentration. At first, we assayed kynurenine concentration of students (n = 13) who took part in a rugby camp for three days. The mean value of kynurenine concentration of before and after training were 1.362 +/- 0.306 microM and 1.725 +/- 0.511 microM respectively. These data means that severe exercise rise the serum kynurenine concentration. Then we tried to examine the relationship between the level of exercise and serum kynurenine concentration. Serum kynurenine concentration had significantly increased immediately after the exercise from 1.869 +/- 0.285 microM to 2.138 +/- 0.248 microM of 24 hours later by loading of 65% heart rate max exercise for each subject. These results suggested that at least the severe exercise affect on the tryptophan metabolism. We will discuss the change of serum kynurenine concentration by another sports such as soccer game and 20 km run.

Chromatography, High Pressure Liquid↗
PubMed1999

[Home medical care from our hospital].

From April, 1996 to March, 1999, our hospital provided home medical care on a 24-hour basis for fifty patients with advanced or terminal cancer. Eventually, twenty-four patients died at home and twenty-six in the hospital. Stability of health status, the presence of willing and able caregivers, as well as a greater number of house-calls are suggested factors in facilitating a death at home. However, the patients who died in the hospital were obliged to readmit themselves until the time of death due to caregivers' reasons such as fatigue, emotional stress and/or health problems. In addition to timely availability and accessibility of respite care, psychosocial support for family caregivers by liaison nurses remains an issue to be solved in future.

Caregivers↗
PubMed1997

The regional vulnerability to blockade of action potentials in organotypic hippocampal culture.

We investigated how blockade of spontaneous action potentials influenced the synaptogenesis by measuring the field population spike using hippocampal organotypic cultures. Although respective blockade of inhibitory and excitatory neurotransmission by picrotoxin and CNQX did not significantly induce cell death in all hippocampal area, sodium channel blocking drugs (tetrodotoxin or lidocaine) caused specific and severe damage and affected the formation of functional synapse in CA1 and the entorhinal cortex but not in CA3. It is suggested that the spontaneous action potentials would play a critical role during synaptogenesis.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1997

Optical recording of trisynaptic pathway in rat hippocampal slices with a voltage-sensitive dye.

Changes in membrane potentials were recorded from rat hippocampal slices with a voltage-sensitive dye using a real-time optical recording system, which had high spatial resolution of 128 x 128 points with a high time resolution of 0.6 ms. Serial excitatory propagation was recorded in the dentate gyrus. CA3 and CA1 after stimulation of the perforant pathway, and the optical signals were clearly divided into two components in the dentate gyrus adjacent to the stimulus site. The slow component was suppressed in Ca(2+)-free solution, but the fast component in the molecular layer was not affected. However, the application of 1 microM tetrodotoxin fully abolished both components. These results suggest that the fast and slow components mainly reflect Na(+)-dependent action potentials and excitatory postsynaptic potentials, respectively. The excitatory response duration in the stratum radiatum of CA3 was significantly longer than that in other hippocampal areas. The long-lasting excitation in CA3 is probably related to the CA3 associational projections, because direct stimulation of CA3 pyramidal cell layer also produced similar results. The long-lasting dendritic excitation is probably important to integrate synaptic transmission and may be related to epileptogenesis. When long-term potentiation was induced by a tetanic stimulation (100 Hz for 1 s), the onset latency in the stratum radiatum of CA1 was reduced to as much as 65%, suggesting an increase of excitatory propagation. The analysis of the spatial-temporal optical signals contributes to understanding information processes in the hippocampus, related to learning and memory including long-term potentiation.

Animals↗
PubMed1997

Basic fibroblast growth factor and brain-derived neurotrophic factor promote survival and neuronal circuit formation in organotypic hippocampal culture.

Neurotrophic effects in vitro have been generally related to promotion of differentiation, maturation and survival, but little is known about the effect on neuronal circuit formation. The organotypic culture system would be an available technique to investigate neuronal circuit formation and neuronal cell-cell interactions. As we reported previously, an optical recording system is a useful technique to comprehend neuronal activities and circuit from multi-points simultaneously. In this study, we investigated whether continuous application of basic fibroblast growth factor (bFGF or FGF-2) and brain-derived neurotrophic factor (BDNF) inhibited neuronal cell death induced by serum-deprivation in organotypic culture using propidium iodide staining, and we analyzed effects of bFGF and BDNF on the formation of neuronal circuits using the optical recording system. Continuous application of bFGF or BDNF significantly protected the slices from neuronal death. Optical recording also demonstrated that addition of 10 ng/ml bFGF or 50 ng/ml BDNF enhanced optical signals in all hippocampal areas significantly. These data strongly suggest that bFGF and BDNF promote the formation of neuronal circuits as well as survival and that optical recording of organotypic hippocampal slices would be a useful technique that enables us to analyze neuronal circuit formation easily.

Animals↗
PubMed1997

[Hospice program and palliative medicine].

Hospice and palliative care have important roles for cancer patients in an incurable state to alleviate their total pain and to achieve the best quality of life. Interdisciplinary team-doctors, nurses, therapists, social workers and so on provide effective support in order to fulfill the varying needs of patients and families. Pain relief as a palliative medicine is most urgently required by seventy percent of patients on admission to our Hospice at the Salvation Army Kiyose Hospital. A case is presented with some comments on pain management. Music therapy is also introduced. This is one of the complementary methods for consolation of the mind and body of patients. Some of them seem to find it beneficial.

Female↗
PubMed1996

Optical recording of rat entorhino-hippocampal system in organotypic culture.

It is difficult to comprehend the entorhino-hippocampal information processing using acute transverse hippocampal slice, because the dorsally inclined connections of the entorhino-hippocampal projections can be damaged easily. Therefore, we investigated the spatial-temporal propagation in organotypic cultures of the hippocampus attaching to the entorhinal cortex using a real-time optical recording system with a voltage-sensitive dye and suitability as an in vitro model. Real-time imaging demonstrated that the stimulation of the perforant pathway induced excitatory propagation in trisynaptic pathway of the hippocampus and sequentially in the layer V from the medial to the lateral entorhinal cortex. The horizontal propagation from the lateral to the medial site was also seen after the stimulation of the lateral entorhinal cortex. The analysis of the entorhino-hippocampal organotypic culture would contribute to understanding of the mechanism of learning and memory.

Animals↗
PubMed1996

3-Hydroxykynurenine toxicity on the rat striatum in vivo.

3-Hydroxykynurenine (3-HK) is a tryptophan metabolite whose level in the brain is elevated under several pathological states including Huntington's disease. In the present study, we examined the possible toxicity of 3-HK by injection of this substance into rat brain. Intrastriatal injection of 3-HK (50 nmol) induced tissue damage around the injected site. Quinolinic acid (QA) at 200 nmol also induced tissue damage, which was comparable in size to that induced by 50 nmol 3-HK. Co-administration of MK-801 significantly reduced QA-induced lesion, but failed to prevent 3-HK-induced lesion. On the other hand, the antioxidant N-acetyl-L-cysteine (10 nmol) reduced 3-HK-induced damage. Thus, 3-HK may be involved in brain pathogenesis by providing oxygen radicals.

Acetylcysteine↗
PubMed1991

[A case of advanced prostatic cancer presenting as inguinal mass].

A 71-year-old man visited our hospital complaining of a nodule in the left inguinal region. Pathological and immunohistochemical examination of the prostate and the mass and clinical examination revealed a case of prostatic cancer with lymph node metastasis, stage D. Chemoendocrine therapy (diethylstilbestrol diphosphate, cisplatin, adriamycin and carboquone) was performed and the patient responded well. This case indicated the presence of an unusual prostatic cancer in which large non-regional superficial lymph node metastasis occurred.

Adenocarcinoma↗
PubMed1989

Effects of protein kinase-C-related adrenocorticotropin secretagogues and interleukin-1 on proopiomelanocortin gene expression in rat anterior pituitary cells.

To examine the effects of the cAMP-independent protein kinase-C system and interleukin-1 (IL-1) on secretion of ACTH and POMC gene expression in cultured rat anterior pituitary (AP) cells, AP cells were incubated with CRF, 8-bromo-cAMP, arginine vasopressin, angiotensin II, norepinephrine, and phorbol 12-myristate 13-acetate. After 15 h of incubation, CRF and 8-bromo-cAMP increased both ACTH release and the POMC mRNA level. Arginine vasopressin, angiotensin II, norepinephrine, or phorbol 12-myristate 13-acetate stimulated ACTH release but failed to increase basal or CRF-stimulated POMC mRNA levels. Human recombinant IL-1 alpha and -beta increased neither ACTH release nor POMC mRNA levels after 3 h of incubation. After 15 h of incubation, 100 pM to 10 nM IL-1 alpha and -beta increased ACTH release. However, POMC mRNA levels were significantly elevated only by 10 pM IL-1 beta. These results suggest that the CRF-cAMP system plays a major role in both ACTH release and expression of the POMC gene in AP cells, but the cAMP-independent protein kinase-C system contributes only to ACTH release; that acute stimulation of ACTH release from AP with IL-1 administration is not due to direct action of IL-1 at the pituitary level; that chronic exposure of AP cells to IL-1 alpha or -beta can stimulate ACTH release; and that the direct effects of IL-1 alpha and -beta on POMC gene expression, if any, seem to be minimal.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1989

Adrenergic modulation of adrenocorticotropin responses to insulin-induced hypoglycemia and corticotropin-releasing hormone.

To study possible adrenergic modulation of pituitary-adrenal responses to insulin-induced hypoglycemia and CRH we examined the effect of nonselective alpha-blockade (phentolamine) and nonselective beta-blockade (propranolol) on plasma ACTH, cortisol, and vasopressin (AVP) responses to hypoglycemia and CRH in five normal men. Infusion of propranolol or phentolamine did not alter basal plasma ACTH or cortisol levels. The propranolol infusion enhanced the stimulatory effect of hypoglycemia on ACTH, cortisol, and AVP secretion and also enhanced the stimulatory effect of CRH on ACTH and cortisol secretion. Infusion of phentolamine inhibited hypoglycemia-induced ACTH and AVP secretion, but had no effect on the stimulatory effect of CRH on ACTH and cortisol secretion. The increments of plasma ACTH and cortisol induced by an almost maximal dose of CRH (1 microgram/kg) were smaller than those induced by hypoglycemia. The propranolol-induced enhancement of the ACTH response to hypoglycemia was almost the same as the ACTH response to CRH alone. From these results we conclude that propranolol may act at the pituitary level to enhance CRH action, rather than AVP action, and that the ACTH response to hypoglycemia may be mediated by hypothalamic alpha-adrenergic activation.

Adrenocorticotropic Hormone↗