Publications by authors named "Kitahama K"

Article Synopsis
  • Advanced pancreatic ductal adenocarcinoma (PDAC) has different subtypes, with the basal-like subtype showing worse prognosis and chemotherapy resistance compared to the classical subtype.
  • This study evaluated immunohistochemistry (IHC) staining of four markers on biopsy samples from 190 untreated advanced PDAC patients, identifying three distinct patterns: Classical, Transitional, and Basal-like.
  • The Basal-like pattern was linked to poorer survival rates and associated with specific histological features, making IHC expression patterns a valuable tool for predicting prognosis and guiding treatment decisions in advanced PDAC.
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Article Synopsis
  • * In a study involving 39 IUP cases, researchers found that 87% had oncogenic mutations in RAS family genes, particularly HRAS, which was linked to smoking and specific morphological traits, while KRAS mutations were only found in non-smokers.
  • * The study revealed no cases of recurrence or progression to cancer during follow-up, emphasizing the role of RAS mutations in IUP development and their relationship to different tumor subtypes and spread patterns.
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Hepatocellular carcinomas (HCCs) with biliary/progenitor cell features frequently show increased programmed death-ligand 1 (PD-L1) expression, but their response to immunotherapy is not high. One possible explanation for this phenomenon could be the loss of major histocompatibility complex (MHC) class I expression on tumor cells, which impairs the presentation of tumor antigens to cytotoxic T cells. However, the potential correlation between MHC class I loss, biliary/progenitor cell features, and the tumor-immune microenvironment remains largely unexplored.

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Although most cases occur in immunocompromised individuals, anal tuberculosis can occur in the absence of HIV infection. Anal tuberculosis should be considered in the differential diagnosis of chronic or recurrent anal fistulas.

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Trimethylation of histone H3 at lysine 27 (H3K27me3) acts as a transcriptional repressor of target genes. Recent immunohistochemical studies have reported a loss of H3K27me3 modification in diffuse (especially 1p/19q-codeleted) gliomas. However, we did not observe H3K27me3 loss in diffuse gliomas using routine immunostaining conditions for the detection of H3K27me3 loss in malignant peripheral nerve sheath tumors (MPNSTs).

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A man aged 66 years presented with pneumaturia as a major complaint. Cancer of the sigmoid colon with infiltration to the urinary bladder was diagnosed and the patient underwent colectomy of the sigmoid colon and partial cystectomy of the bladder in May 2015. Histopathologic examinations revealed pT4b, Si(bladder), pN(-), cM0, fStage II .

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The objective of the present study was to determine with precision the localization of neurons and fibers immunoreactive (ir) for aromatic L-amino acid decarboxylase (AADC), the second-step enzyme responsible for conversion of L-dihydroxyphenylalanine (L-DOPA) to dopamine (DA) and 5-hydroxytryptophan (5-HTP) to serotonin (5-hydroxytryptamine: 5-HT) in the midbrain, pons, and medulla oblongata of the adult human brain. Intense AADC immunoreactivity was observed in a large number of presumptive 5-HT neuronal cell bodies distributed in all of the raphe nuclei, as well as in regions outside the raphe nuclei such as the ventral portions of the pons and medulla. Moderate to strong immunoreaction was observable in presumptive DA cells in the mesencephalic reticular formation, substantia nigra, and ventral tegmental area of Tsai, as well as in presumptive noradrenergic (NA) cells, which were aggregated in the locus coeruleus and dispersed in the subcoeruleus nuclei.

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Ozone (O3) is widely distributed in the environment, with high levels of air pollution. However, very few studies have documented the effects on postnatal development of O3 during pregnancy. The long-term effects of prenatal O3 exposure in rats (0.

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Ozone, a major photochemical pollutant, produces rapid damages in the pulmonary airway tract and in the central nervous system. This study focused on the neural mechanisms underlying the adaptive responses to an acute ozone exposure. Vascular endothelial growth factor (VEGF) is a factor associated with cellular recovery following brain injury.

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The present study examined dopamine-immunoreactive neuronal structures using immunohistochemistry in conjunction with an anti-dopamine antiserum, following injection of l-3,4-dihydroxyphenylalanine (L-DOPA) with or without an inhibitor of monoamine oxidase (Pargyline) in the cat brain. L-DOPA injection made it possible to detect dopamine immunoreactivity in presumptive serotonergic and noradrenergic cell bodies and axons. Weak to moderate dopamine immunoreactivity was observed in non-aminergic cells (possibly so-called "D" cells containing aromatic L-amino acid decarboxylase (AADC)) in several hypothalamic, midbrain, pontine and medullary nuclei.

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[Brain and sleep mechanism].

Rinsho Shinkeigaku

November 2006

It is now accepted that sleep is induced by biological clock located in the suprachiasmatic nucleus and/or sleep promoting substances, which influence ventrolateral preoptic (VLPO) neurons. The VLPO neurons affects more caudally situated posterior hypothalamic ones containing orexine and/or histamine, reciprocally. When these neurons inhibit lower brainstem aminergic ones, sleep is induced.

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8-oxoguanine DNA glycosylase and Kin17 are proteins widely distributed and phylogenetically conserved in the CNS. 8-oxoguanine DNA glycosylase is a DNA repair enzyme that excises 7,8-dihydro-8-oxoguanine present in DNA damaged by oxidative stress. Kin17 protein is involved in DNA repair and illegitimate recombination in eukaryotic cells.

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Immunoreactivity to p-tyramine, one of the natural trace amines, was studied in the rat brain by an anti-p-tyramine antibody. Immunoreactivity to this amine is very weak in the nigrostriatal dopaminergic neurons and terminals, and weak in the locus coeruleus noradrenergic ones. It was intensified in these structures after monoamine oxidase inhibition.

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We previously reported that an eight hour phase advance in the light-dark (LD) cycle increases sleep in rats. Brain-derived neurotrophic factor (BDNF) is suggested to be one of the sleep and circadian regulating factors. We have therefore observed the responses of BDNF protein in the hippocampus, cerebellum and brainstem under conditions of LD change.

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Historically, 3,4-dihydroxyphenylalanine (DOPA) has been believed to be an inert amino acid that alleviates the symptoms of Parkinson's disease by its conversion to dopamine via the enzyme aromatic L-amino acid decarboxylase. In contrast to this generally accepted idea, we propose that DOPA itself is a neurotransmitter and/or neuromodulator, in addition to being a precursor of dopamine. Several criteria, such as synthesis, metabolism, active transport, existence, physiological release, competitive antagonism, and physiological or pharmacological responses, must be satisfied before a compound is accepted as a neurotransmitter.

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Since very few previous studies have carried out the quantitative analysis for the colocalization of nitric oxide (NO) and vasoactive intestinal peptide (VIP) in the submucous neurons in the rat digestive tract, we applied in vivo treatment of colchicine to enhance the immunoreactivity and examined the colocalization of NO synthase (nNOS) and VIP in neurons of the submucous plexus throughout the rat digestive tract. The density of nNOS-containing neurons in the submucous plexus in the stomach corpus (103+/-25 cells/cm(2), n=3) and that in the antrum (157+/-9 cells/cm(2), n=3) were significantly lower than those in small and large intestine. However no difference was detected in the cell density among duodenum (1967+/-188 cells/cm(2), n=3), jejunum (2640+/-140 cells/cm(2), n=3), ileum (2070+/-42 cells/cm(2), n=3), proximal colon (2243+/-138 cells/cm(2), n=3) and distal colon (2633+/-376 cells/cm(2), n=3).

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This study reports the presence of noradrenergic (NA) neurons which are capable to take up 5-hydroxytryptophan (5-HTP) and decarboxylate it to 5-hydroxytryptamine (5-HT serotonin) in the kitten brain. After loading of 5-HTP and monoamine oxidase inhibitor (MAOI), we could demonstrate 5-HT-immunoreactivity (IR) not only in hypothalamic and midbrain dopaminergic (DA) cell bodies, but also in NA ones located in the pons and medulla oblongata of the new born kitten aged from 1 to 7 days. NA cell bodies could no longer show 5-HT-IR after this treatment in the kitten older than 1 month.

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Background: Aromatic L-amino acid decarboxylase (AADC) is the enzyme responsible for the decarboxylation step in both the catecholamine and indoleamine synthetic pathways. In the brain, however, a group of AADC containing neurones is found outside the classical monoaminergic cell groups. Since such non-monoaminergic AADC is expressed abundantly in the suprachiasmatic nucleus (SCN), the mammalian circadian centre, we characterized the role of AADC in circadian oscillation.

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We studied the immunohistochemical localization of neuronal nitric oxide synthase (nNOS) in the developing rat brain on embryonic days 13 (E13), 15 (E15), 17 (E17) and 19 (E19) and postnatal days 0 (P0), 7 (P7) and 14 (P14). A few neurons positive for nNOS were first detected at E15 in the hypothalamus and pons. At E17, many positive cells became detectable in the thalamus.

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The effects of the carotenoids beta-carotene and astaxanthin on the peroxidation of liposomes induced by ADP and Fe(2+) were examined. Both compounds inhibited production of lipid peroxides, astaxanthin being about 2-fold more effective than beta-carotene. The difference in the modes of destruction of the conjugated polyene chain between beta-carotene and astaxanthin suggested that the conjugated polyene moiety and terminal ring moieties of the more potent astaxanthin trapped radicals in the membrane and both at the membrane surface and in the membrane, respectively, whereas only the conjugated polyene chain of beta-carotene was responsible for radical trapping near the membrane surface and in the interior of the membrane.

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We previously proposed that L-3,4-dihydroxyphenylalanine (L-DOPA) is a neurotransmitter in the CNS. Receptor and transporter molecules for L-DOPA, however, have not been determined. In the present study, in order to localize the uptake sites of L-DOPA in the CNS, we performed autoradiographic uptake studies using L-[14C]DOPA and L-[3H]DOPA in the uptake study on rat brain slice preparations, and further analyzed the properties of L-DOPA uptake.

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The two mesencephalic dopaminergic systems in the developing rat brain were investigated immunohistochemically by dopamine and tyrosine hydroxylase and the results were quantitatively analyzed with a computer. The number of the dopaminergic neurons in the substantia nigra and the ventral tegmentum area did not change significantly during the postnatal development. Dopaminergic terminals in the lateral septum peaked at postnatal days (PD) 30, when the cell size in middle third of the ventral tegmentum area which was suggested as an origin of this projection system, increased largely.

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