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Biomedical subjects

K Nakashima

Publications and source records attributed to K Nakashima.

At least 145 records · Page 8Linked to original sources
PubMed2000

Hyphenated chromatographic methods for biomaterials.

The improvement in hyphenated analytical techniques has significantly widened their applications to the analysis of biomaterials. In this article, we discuss recent advances in applications of hyphenated chromatographic techniques including capillary electrophoresis to the analyses of biological samples. As tools of separation, gas chromatography, high-performance liquid chromatography and capillary electrophoresis are considered with special emphasis on applications utilizing the hyphenation of these methods to mass spectrometry. Moreover, applications using other detection methods such as Fourier transform infrared spectroscopy hyphenated to gas chromatography and photodiode array detector combined with high-performance liquid chromatography or capillary electrophoresis are also discussed. Owing to their high sensitivity, luminescence-based detection systems such as laser-induced fluorescence and chemiluminescence are also included in this review.

Animals↗
PubMed2000

Molecular cloning of the chicken prolactin gene and activation by Pit-1 and cAMP-induced factor in GH3 cells.

Transcription of the prolactin (PRL) gene has been reported to be activated by a nuclear factor, Pit-1. However, the precise molecular mechanisms of the Pit-1-mediated PRL gene activation are still unclear. We have cloned the chicken PRL (cPRL) gene and its 5'-flanking region to analyze their structure and transcription-initiating mechanism. In luciferase assay, forskolin activated the proximal promoter region between -248 and -76 to transcribe the cPRL gene in GH3 cells, although there is no canonical cyclic AMP-responsive element in the promoter region. In gel mobility shift assay, a DNA fragment between -104 and -76 containing a putative Pit-1 binding site was bound by nuclear factors from the GH3 cells. Furthermore, it was observed that Pit-1 protein specifically bound to the DNA fragment in the supershift assay. These results indicate that both Pit-1 and cAMP-induced factor(s) associated with the cis element on the proximal promoter region to activate cPRL gene expression in GH3 cells.

Animals↗
PubMed2000

Tissue oxygen pressure during prolonged ischemia of the liver.

BACKGROUND: The potential role of hepatovenous back-perfusion in maintaining organ viability of the inflow-occluded liver has been reported with respect to aspects of tissue perfusion and energy metabolism. In the present study, the physiological differences between liver ischemia induced by portal triad clamping (PTC) and that induced by total hepatic vascular exclusion (THVE) were investigated in a porcine disease model, with special reference to changes in tissue oxygen pressure (PtO(2)) of the liver. MATERIALS AND METHODS: Twelve female pigs were used for induction of 60 min of normothermic liver ischemia. They were assigned to two groups: a PTC group (n = 6) and a THVE group (n = 6). PtO(2) was measured before, during, and after the ischemic period at two different points in the middle lobe: on the central side close to the hepatovenous confluence and on the peripheral side close to the gallbladder bed. RESULTS: Although central PtO(2) decreased during ischemia in both groups, PTC group values at 40 and 60 min of ischemia remained significantly higher than THVE group values (60 +/- 28 and 42 +/- 21 mmHg vs 11 +/- 5 and 13 +/- 3 mmHg, respectively; means +/- SD). Peripheral PtO(2) in the PTC group during ischemia was low in comparison to corresponding central PtO(2) values. CONCLUSION: Oxygen supply to the tissue via hepatovenous reflux may contribute to maintaining organ viability under prolonged inflow occlusion of the liver.

Animals↗
PubMed2000

Advanced glycation endproduct-modified superoxide dismutase-1 (SOD1)-positive inclusions are common to familial amyotrophic lateral sclerosis patients with SOD1 gene mutations and transgenic mice expressing human SOD1 with a G85R mutation.

To clarify the biological significance of the neuronal Lewy body-like hyaline inclusions and astrocytic hyaline inclusions characteristically found in patients with familial amyotrophic lateral sclerosis with superoxide dismutase-1 (SOD1) gene mutations and in transgenic mice expressing human SOD1 with G85R mutation, the detailed protein composition in both types of inclusions was immunohistochemically analyzed using 45 different antibodies. Both types of inclusions had very strong immunoreactivity for SOD1. The SOD1-positive inclusions in both cell types were also immunoreactive for the insoluble advanced glycation endproducts (AGEs) such as Nepsilon-(carboxymethyl)lysine (CML), pyrraline and pentosidine: both inclusions in both conditions were ultrastructurally composed of the granule-coated fibrils that had immunoreactivities to CML and pyrraline. Both types of inclusions were negative for stress-response proteins (SRPs), 4-hydroxy-2-nonenal (HNE), acrolein, nitric oxide synthases (NOSs) and nitrotyrosine as representative markers of oxidative stress. The neurons and astrocytes of the normal individuals and non-transgenic mice showed no significant immunoreactivity for SOD1, AGEs, SRPs, HNE, acrolein, NOSs or nitrotyrosine. Our results suggest that a portion of the SOD1 composing both type of inclusions, probably toxic mutant SOD1, is modified by the AGEs, and that the formation of the AGE-modified SOD1 is one of the mechanisms responsible for the aggregation involving no significant oxidative mechanisms.

Adult↗
PubMed2000

Multiple hepatic adenomas caused by long-term administration of androgenic steroids for aplastic anemia in association with familial adenomatous polyposis.

We report a rare case of hepatic adenomas (HA), in a 20-year-old Japanese girl treated for 6 years with anabolic androgens for aplastic anemia. In a review of the world literature using computer MEDLINE search, we found only 17 cases of androgen-induced HA published between 1975 and 1998 in the English-language literature. The patient was referred to us because of liver lesions detected during a follow-up examination for familial adenomatous polyposis. After being diagnosed with aplastic anemia at 14 years of age, she had been treated with oxymetholone (30 mg/day) for 6 years. Laboratory evaluation revealed normal liver function. Ultrasonography (US) and computed tomography (CT) demonstrated multiple liver lesions. Histopathological examinations of biopsied specimens from the liver tumor showed HA. After the patient was diagnosed with HA, oxymetholone was tapered off. Patients taking androgenic-anabolic steroids should be carefully monitored with US and CT and tumor markers should be measured. This report may be helpful in identifying the population who is at risk of developing hepatic sex hormone-related tumors.

Adenoma↗
PubMed2000

Four alkaloids, lucidine B, oxolucidine A, lucidine A, and lucidulinone from Lycopodium lucidulum.

The structures of four alkaloids extracted from Lycopodium lucidulum (Lycopodiaceae) were established by X-ray and 2D NMR spectroscopic analyses. The dihydro-derivative of oxolucidine A, which was obtained by NaBH4 reduction of oxolucidine A, was treated with p-bromobenzoyl chloride to afford crystals, whose X-ray crystallographic analysis established the stereostructure, including the absolute configuration. The 2D NMR spectra of tetrahydrodeoxylucidine B were fully analyzed to establish the full structure of lucidine B, and the hitherto unknown stereochemistry at the C-14 position was established as beta-H. The structure of a new alkaloid, lucidulinone, was determined by spectroscopic analysis to be luciduline lactam.

Alkaloids↗
PubMed2000

Trichosporon cutaneum (Trichosporon asahii) infection mimicking hand eczema in a patient with leukemia.

Trichosporon Cutaneum is a yeast-like fungus that causes white piedra and onychomycosis. Recently, it has also been recognized as an opportunistic pathogen in immunocompromised hosts. We describe a 64-year-old woman who developed a superficial Trichosporon infection mimicking hand eczema during chemotherapy for her chronic myelocytic leukemia. To our knowledge, no cases of superficial infection like this one have previously been reported. This case suggests that careful examination is required in diagnosing Trichosporon infection in immunocompromised hosts, because the infection can be invasive or unusual in appearance.

Anti-Infective Agents, Local↗
PubMed2000

Organization and expression of two Arabidopsis DREB2 genes encoding DRE-binding proteins involved in dehydration- and high-salinity-responsive gene expression.

In plants, a cis-acting element, DRE/CRT, is involved in ABA-independent gene expression in response to dehydration and low-temperature stress. To understand signal transduction pathways from perception of the dehydration stress signal to gene expression, we characterized a gene family for DRE/CRT-binding proteins DREB2A and DREB2B in Arabidopsis thaliana. Northern analysis showed that both genes are induced by dehydration and high-salt stress. Organ-specific northern analysis with gene-specific probes showed that these genes are strongly induced in roots by high-salt stress and in stems and roots by dehydration stress. The DREB2A gene is located on chromosome 5, and DREB2B on chromosome 3. We screened an Arabidopsis genomic DNA library with cDNA fragments of DREB2A and DREB2B as probes, and isolated DNA fragments that contained 5'-flanking regions of these genes. Sequence analysis showed that both genes are interrupted by a single intron at identical positions in their leader sequence. Several conserved sequences were found in the promoter regions of both genes. The beta-glucuronidase (GUS) reporter gene driven by the DREB2 promoters was induced by dehydration and high-salt stress in transgenic Arabidopsis plants.

Arabidopsis↗
PubMed2000

Extraosseous epidural IgD myeloma presenting with compression myelopathy.

An 85-year-old man presented with acute transverse myelopathy: flaccid paraplegia, superficial and deep sensory disturbance below Th6 and loss of urinary sensation. Spinal magnetic resonance image showed an epidural mass compressing the spinal cord at the level of C7 to Th2. Immunoelectrophoresis revealed the presence of immunoglobulin D (IgD)-lambda M protein. Chemotherapy markedly improved both the haematologic aspect and tumor size, but not the motor deficit. In IgD myeloma, extraosseous spreads occur frequently, but extraosseous epidural tumors causing compression myelopathy are relatively rare. To our knowledge, this is the fourth report of cases.

Aged↗
PubMed2000

Astrocyte differentiation of fetal neuroepithelial cells by interleukin-11 via activation of a common cytokine signal transducer, gp130, and a transcription factor, STAT3.

The interleukin (IL)-6 family cytokines utilize membrane glycoprotein gp130 in common as a critical signal-transducing receptor component. IL-11, a cytokine initially identified as a plasmacytoma growth factor, belongs to this family. We show here that IL-11 and its cognate receptor components are expressed in fetal mouse neuroepithelial cells. We also show that after 4 days of culture with IL-11, cells with typical astrocytic morphologies expressing glial fibrillary acidic protein (GFAP; a marker for astrocytes) come out. This differentiation process is totally dependent on the gp130-mediated signal-transduction pathway involving activation of a latent cytoplasmic transcription factor, STAT3 (for signal transducer and activator of transcription 3), because (a) IL-11-induced astrocyte differentiation is not observed when neuroepithelial cells prepared from gp130-deficient mice were used, (b) stimulation of neuroepithelial cells by IL-11 rapidly induces tyrosine-phosphorylation of STAT3, and (c) transfection of neuroepithelial cells with a dominant-negative form of STAT3 inhibits IL-11-induced activation of the GFAP gene promoter. We have further identified, in the GFAP promoter region, a STAT3 site at which nucleotide substitutions almost completely abolished the IL-11-induced GFAP promoter activation. Taken together, it is suggested that IL-11 contributes to astrocytogenesis in fetal brain via activation of gp130 and STAT3.

Animals↗
PubMed2000

Cosinor analysis of heart rate variability in ambulatory migraineurs.

OBJECTIVE: To clarify whether the circadian rhythm of heart rate variability parameters can be identified in patients with migraine during a headache-free period and to identify any specific pattern of the circadian rhythm of heart rate variability, using time-domain and spectral analysis and cosinor rhythm analysis of heart rate variability during normal daily activity. METHODS: Forty-eight-hour Holter electrocardiograms were recorded for 27 patients with migraine during headache-free periods and 24 healthy controls during free activity. The circadian rhythms of heart rate fluctuation parameters, that is, mean interval, standard deviation, root-mean-square successive differences (RMSSD), %RR50, and low (0. 020 to 0.150 Hz) and high frequency (0.150 to 0.400 Hz) heart rate fluctuations were analyzed with the group mean cosinor method. RESULTS: The group mean cosinor analysis and the acrophase-amplitude analysis demonstrated significant differences in circadian rhythm in SD, RMSSD, %RR50, and high frequency between the group with migraine and controls. The amplitudes of SD, RMSSD, %RR50, and high frequency in the group with migraine were smaller than those in controls, which implied parasympathetic hypofunction in migraineurs. There were no significant differences in the MESOR (midline estimating statistic of rhythms) of the analyzed heart rate parameters except for low frequency. The MESOR of low frequency in the migraineurs was significantly smaller than that in the controls. CONCLUSIONS: Patients with migraine have hypofunction in the parasympathetic nervous system during normal daily activity in the headache-free period.

Adolescent↗
PubMed2000

Frameshift, nonsense and non amino acid altering mutations in SOD1 in familial ALS: report of a Japanese pedigree and literature review.

We demonstrated the clinical characteristics of each member of a family from Oki Island in western Japan, whose members have familial amyotrophic lateral sclerosis (FALS) with a 2-base pair (bp) deletion at codon 126 of Cu/Zn superoxide dismutase (SOD1) gene. Mean disease duration among the Oki family members was about 2 years. Long-term survivors with respiratory support presented disturbances in eye movement and urination toward the end stages of the disease. In addition, we focused on in-vitro instabilities in the frameshift and nonsense mutations, including the 2-bp deletion, as well as some deletional, insertional and intronic mutations. These mutations were all found within exon 4, exon 5 and intron 4. As for the durations of illness, there were no significant differences between FALS patients with these SOD1 mutations and those with point mutations, although the former cases were likely to have shorter disease durations. In cell culture experiments, SOD1 proteins with frameshift and nonsense mutations were extremely unstable and showed very short half-lives. We postulated that the in-vitro instability of the mutant SOD1 might be related to the pathogenesis of FALS, e.g. through the mechanism of copper release.

Amyotrophic Lateral Sclerosis↗
PubMed2000

New consensus research on neuropathological aspects of familial amyotrophic lateral sclerosis with superoxide dismutase 1 (SOD1) gene mutations: inclusions containing SOD1 in neurons and astrocytes.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that primarily involves the motor neuron system. Approximately 5-10% of ALS is familial. Superoxide dismutase 1 (SOD1) gene mutations are shown to be associated with about 20% of familial ALS (FALS) patients. The neuronal Lewy-body-like hyaline inclusion (LBHI) and astrocytic hyaline inclusion (Ast-HI) are morphological hallmarks of certain SOD1-linked FALS patients with SOD1 gene mutant and transgenic mice expressing human SOD1 with G85R mutation. From the detailed immunohistochemical analyses, the essential common protein of both inclusions is SOD1. Ultrastructurally, both inclusions consist of granule-coated fibrils 15-25 nm in diameter. Based on the immuno-electron microscopical finding that these abnormal granule-coated fibrils are positive for SOD1, the formation (or aggregation) of the abnormal fibrils containing SOD1 would be essential evidence in diseases caused by various SOD1 mutations. The granule-coated fibrils are also modified by advanced glycation end products (AGEs). The AGEs themselves are insoluble molecules with direct toxic effects on cells. AGE formation of SOD1 composing the granule-coated fibrils (probable AGE-modified mutant SOD1) may amplify their aggregation and produce a more marked toxicity.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Responses to umami substances in taste bud cells innervated by the chorda tympani and glossopharyngeal nerves.

The chorda tympani (CT) and glossopharyngeal (GL) nerves of several mammalian species respond differently to umami substances (US) such as monosodium glutamate (MSG), disodium 5'-inosinate (IMP) and disodium 5'-guanylate (GMP). In mice and rhesus monkeys, responses to US are greater in the GL than the CT nerve, with the GL nerve containing larger numbers of MSG-sensitive fibers. Gurmarin, a sweet response inhibitor, suppresses the mouse CT responses to the mixture of MSG and IMP to approximately 65% of control levels but not to the metabotropic and ionotropic glutamate agonists 2-amino-4-phophonobutyrate and N-methyl-D-aspartate. Gurmarin does not inhibit any taste responses in the GL. In mice, CT responses to MSG may be masked by their greater sensitivity to sodium ions. Calcium imaging studies demonstrate that some mouse taste cells isolated from the fungiform papilla innervated by the CT respond selectively (as indicated by a rise in intracellular Ca(2+) concentrations) to MSG and/or IMP or GMP. These MSG responses are not suppressed notably by reducing the Ca(2+) concentration of the stimulus solution, suggesting that the observed Ca(2+) release is from intracellular stores. Measurements of second messengers in the mouse fungiform papilla have revealed consistently that MSG elicits increases in both inositol 1,4,5-trisphosphate and adenosine 3', 5'-cyclic monophosphate levels. Together, these results suggest that US may stimulate two different transduction mechanisms in the fungiform papilla. They also suggest that gurmarin-insensitive components of receptors for US, including metabotropic and ionotropic glutamate receptors, may be commonly involved in transduction for umami taste in taste cells on both anterior and posterior parts of the tongue.

Animals↗
PubMed2000

Identification of a novel WD repeat-containing gene predominantly expressed in developing and regenerating neurons.

In the present study, we have identified a novel gene, NDRP (for neuronal differentiation-related protein), which is predominantly expressed in developing and regenerating neurons. The predicted NDRP comprises 1,019 amino acid residues and has 6 WD repeats in the N-terminal half and multiple potential nuclear localization signals (NLSs) at the C-terminal part. This molecule shows no significant structural similarity with any other molecules in available databases. In situ hybridization and immunohistochemistry revealed the highest expression of NRDP in sensory neurons, for instance, olfactory epithelia and neural layer of retina during embryonic development, as well as in perinatal dorsal root ganglions. The expression of this gene in intact motor neurons such as in the hypoglossal nerve was undetectable but became obvious after axotomy. These results suggest that the product of this gene might be involved in the development of sensory neurons as well as the regeneration of motor neurons.

Amino Acid Sequence↗
PubMed2000

A peptide vaccine that prevents experimental autoimmune myasthenia gravis by specifically blocking T cell help.

Myasthenia gravis (MG) and its animal model, experimental autoimmune (EA) MG, are caused by T cell-dependent autoantibodies that react with the nicotinic acetylcholine receptor (AChR) on muscle and interfere with neuromuscular transmission. Thus, selective inactivation of CD4(+) AChR-specific T helper cells should lower AChR Ab levels and ameliorate disease. In the Lewis rat model of EAMG, alpha chain residues 100-116 of the AChR represent the dominant T cell epitope, which is important in helping Ab responses to this autoantigen. In the present report, we have applied a new design technique that requires no knowledge of Ag receptor sequences on errant T cells in order to develop a synthetic peptide vaccine against T cells reactive with the aforementioned T cell epitope. Immunization with the peptide 1) induced polyclonal and monoclonal Ab, which inhibited AChR 100-116 stimulation of AChR-sensitized lymphocytes and recognized Vbeta15 containing T cell receptors on AChR 100-116-specific T cell lines and clones; 2) lowered AChR Ab levels; 3) reduced the loss of muscle AChR; and 4) lessened the incidence and severity of EAMG. These findings suggest a new strategy for the functional abrogation of epitope-specific T cells that could have potential application to human autoimmune diseases.

Amino Acid Sequence↗
PubMed2000

Mutations in the FIE and MEA genes that encode interacting polycomb proteins cause parent-of-origin effects on seed development by distinct mechanisms.

In flowering plants, two cells are fertilized in the haploid female gametophyte. Egg and sperm nuclei fuse to form the embryo. A second sperm nucleus fuses with the central cell nucleus, which replicates to generate the endosperm, a tissue that supports embryo development. The FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) and MEDEA (MEA) genes encode WD and SET domain polycomb proteins, respectively. In the absence of fertilization, a female gametophyte with a loss-of-function fie or mea allele initiates endosperm development without fertilization. fie and mea mutations also cause parent-of-origin effects, in which the wild-type maternal allele is essential and the paternal allele is dispensable for seed viability. Here, we show that FIE and MEA polycomb proteins interact physically, suggesting that the molecular partnership of WD and SET domain polycomb proteins has been conserved during the evolution of flowering plants. The overlapping expression patterns of FIE and MEA are consistent with their suppression of gene transcription and endosperm development in the central cell as well as their control of seed development after fertilization. Although FIE and MEA interact, differences in maternal versus paternal patterns of expression, as well as the effect of a recessive mutation in the DECREASE IN DNA METHYLATION1 (DDM1) gene on mutant allele transmission, indicate that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms.

Arabidopsis↗