Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 55 records · Page 3Linked to original sources

PubMed2002

Effect of Brn-3a deficiency on nociceptors and low-threshold mechanoreceptors in the trigeminal ganglion.

Immunohistochemistry for protein gene product 9.5 (PGP 9.5, a neuron specific protein) and vanilloid receptor 1-like receptor (VRL-1, a marker for medium-sized to large primary nociceptors) were used to assess the effects of Brn-3a deficiency on neuronal innervation of oral tissues and neurons of the trigeminal ganglion (TG). In the knockout mouse, the number of PGP 9.5-immunoreactive (-ir) nerve fibers decreased in the facial cutaneous and oral mucous epithelia, as well as the incisor and molar tooth germs. The reduction of PGP 9.5-ir Merkel endings was also observed in some vibrissae. No obvious change was detected in other tissues. Cell size analysis demonstrated that the proportion of small neurons markedly increased while that of medium-sized and large neurons significantly decreased in the TG of the mutant. Moreover, Brn-3a deficiency caused the disappearance of TG neurons which were immunoreactive for VRL-1. Together, our data suggest that nociceptors and low-threshold mechanoreceptors with medium-sized to large cell bodies may be sensitive to the loss of Brn-3a.

Afferent Pathways↗

PubMed2002

Co-expression of VRL-1 and calbindin D-28k in the rat sensory ganglia.

The co-expression of vanilloid receptor 1-like receptor (VRL-1), a newly cloned capsaicin-receptor homologue, with calbindin D-28k was examined in the rat sensory ganglia. The co-expression was rare in the dorsal root, trigeminal and jugular ganglia and abundant in the petrosal and nodose ganglia. In the dorsal root ganglion, none of VRL-1-immunoreactive (ir) neuron co-expressed calbindin D-28k-immunoreactivity (ir). Of the VRL-1-ir neurons, 9 and 5% showed calbindin D-28k ir in the trigeminal and jugular ganglia, respectively. On the other hand, 35 and 63% of VRL-1-ir neurons in the petrosal and nodose ganglia, respectively, co-expressed these substances. The retrograde tracing method indicated that petrosal neurons which co-expressed VRL-1-and calbindin D-28k-ir innervated taste buds in the circumvallate papilla. The present findings may suggest that VRL-1 is associated with chemosensory functions in visceral sensory neurons.

Animals↗

PubMed2002

Effect of Brn-3a deficiency on parvalbumin-, calbindin D-28k-, calretinin- and calcitonin gene-related peptide-immunoreactive primary sensory neurons in the trigeminal ganglion.

Immunohistochemistry for parvalbumin, calbindin D-28k, calretinin and calcitonin gene-related peptide (CGRP) was performed on the trigeminal ganglion and oro-facial tissues in Brn-3a wildtype and knockout mice at embryonic day 18.5 and postnatal day 0. In wildtype mice, the trigeminal ganglion contained abundant parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while the ganglion was almost devoid of calretinin-immunoreactive neurons. In Brn-3a knockout mice, a 63% decrease of parvalbumin-immunoreactive neurons was detected. In contrast, the absence of Brn-3a dramatically increased the number of calbindin D-28k-immunoreactive (3.5-fold increase) and calretinin-immunoreactive neurons (91-fold increase). The number of CGRP-immunoreactive neurons, however, was not altered by the Brn-3a deficiency. Cell size analysis indicated that loss of Brn-3a increased the proportions of small (<100 microm (2)) parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while it decreased those of large (>200 microm(2)) immunoreactive cells. Calretinin-immunoreactive neurons were either small or medium (100-200 microm (2)) in mutant mice. The oro-facial tissues contained parvalbumin-, calbindin D-28k- and CGRP-immunoreactive fibers, but not calretinin-immunoreactive ones in wildtype mice. In Brn-3a knockout mice, the number of parvalbumin-immunoreactive fibers markedly decreased in the infraorbital nerve and parvalbumin-immunoreactive endings disappeared in the vibrissa. In contrast, the number of calbindin D-28k-immunoreactive fibers increased significantly in the infraorbital and mental nerves. In addition, calbindin D-28k-immunoreactive endings appeared in the vibrissa. As well, some fibers showed calretinin-immunoreactivity in the infraorbital nerve of the mutant. However, no obvious change of CGRP-immunoreactive fibers was observed in the oro-facial region of knockout mice. Taken together, our data suggest that Brn-3a deficiency has effects on the expression of neurochemical substances in the trigeminal ganglion.

Animals↗

PubMed2002

Potential involvement of the AML1-MTG8 fusion protein in the granulocytic maturation characteristic of the t(8;21) acute myelogenous leukemia revealed by microarray analysis.

The AML1 (RUNX1)-MTG8 (ETO) fusion transcription factor generated by the t(8;21) translocation is believed to deregulate the expression of genes that are crucial for normal differentiation and proliferation of hematopoietic progenitors, resulting in acute myelogenous leukemia. To elucidate the role of AML1-MTG8 in leukemogenesis, we used oligonucleotide microarrays to detect alterations in gene expression caused by ectopic expression of AML1-MTG8 in a murine myeloid progenitor cell line, L-G. Microarray analysis of approximately 6500 genes identified 32 candidate genes under the downstream control of AML1-MTG8. Among the 32 genes, 23 were not known to be regulated by AML1-MTG8. These included many granule protein genes and several cell surface antigen genes. Interestingly, AML1-MTG8 enhanced the expression of several genes that are usually induced during granulocytic differentiation, particularly those encoding azurophil granule proteins, including cathepsin G, myeloperoxidase and lysozyme. This indicates that AML1-MTG8 induces partial differentiation of myeloid progenitor cells into promyelocytes in the absence of the usual differentiation signals, while it inhibits terminal differentiation into mature granulocytes. Thus, AML1-MTG8 itself may play a crucial role in defining a unique cytologic type with abnormal maturation, characteristic of t(8;21) acute myelogenous leukemia.

Acute-Phase Proteins↗

PubMed2002

Role of elastase and active oxygen species in gastric mucosal injury induced by aspirin administration in Helicobacter pylori-infected Mongolian gerbils.

BACKGROUND: H. pylori infection potentiates aspirin-induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils. AIM: To determine the role of elastase and active oxygen species (AOS) produced by activated neutrophils in the gastric mucosal injury induced by administration of acidified aspirin to H. pylori-infected Mongolian gerbils. METHODS: H. pylori ATCC43504 culture broth was administered by oral gavage to male Mongolian gerbils at 7 weeks of age. After 4 weeks, acidified aspirin (400 mg/kg) was administered orally, and 3 h later, the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemo-attractive cytokine in rodents) were measured in gastric mucosa. To determine the role of elastase or AOS derived from neutrophils in these circumstances, ONO-5046 (an elastase inhibitor), a combination of superoxide dismutase (SOD) and catalase (scavengers of AOS), and polaprezinc (an anti-ulcer agent with anti-inflammatory effects) were administered before aspirin. RESULTS: ONO-5046 inhibited the increase in gastric erosions and mucosal TBARS induced by administration of aspirin to H. pylori-infected gerbils, but not the increases in MPO activity or KC/GRO contents. A combination of SOD and catalase or polaprezinc significantly reduced gastric erosions, TBARS concentrations, MPO activity and KC/GRO concentration. CONCLUSIONS: These results suggest that neutrophil-derived-elastase and -oxidants play an important role in the gastric mucosal injury induced by administration of aspirin to H. pylori-infected gerbils.

Animals↗

PubMed2002

Helicobacter pylori infection potentiates aspirin induced gastric mucosal injury in Mongolian gerbils.

BACKGROUND: Helicobacter pylori infection and non-steroidal anti-inflammatory drugs are two major causes of gastric ulceration but interactions between H pylori and these drugs in gastric mucosal injury are unclear. AIMS: We studied the influence of experimental H pylori infection on gastric mucosal injury induced by aspirin. SUBJECTS: Male Mongolian gerbils free of specific pathogens were used. METHODS: H pylori ATCC43504 culture broth was administered by oral gavage at seven weeks of age. After three weeks, acidified aspirin (400 mg/kg) was administered orally, and three hours later the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemoattractive cytokine in rodents) were measured in gastric mucosa. To determine the role of neutrophils in these circumstances, antigerbil neutrophil rabbit serum (ANS) was administered to some animals 18 hours before aspirin. RESULTS: Aspirin caused more extensive haemorrhagic erosions (33.1 (12.3) mm2) associated with greater MPO activity (1887.7 (598.5) microU/mg protein) and TBARS (0.33 (0.14) nmol/mg protein) and KC/GRO concentrations (28.3 (9.5) pg/mg protein) in infected than in uninfected gerbils (13.7 (2.3); 204.0 (68.9); 0.12 (0.06); 3.1 (0.8), respectively) Pretreatment with ANS inhibited the increases in gastric erosions, MPO activity, and TBARS but not KC/GRO concentration. The reduction in aspirin induced mucosal injury by administration of ANS was much greater in H pylori infected animals (65%) than in uninfected animals (31%). CONCLUSIONS: H pylori infection potentiates aspirin induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.

Animals↗

PubMed2002

[Congenital tracheoesophageal fistula; report of an adult case].

We experienced an adult case of congenital tracheoesophageal fistula which was successfully treated by surgical intervention. A 69-year-old female was admitted with complaint of coughing and fever. The patient previously had had several episodes of pneumonia. Esophagography and thoracic CT demonstrated a tracheoesophageal fistula in the upper of the thoracic esophagus. Following the resection of the fistula, the trachea was closed with one layer suture and the esophagus was closed with two layer sutures. A pedicled fifth intercostal muscle was interposed between the tracheal and esophageal suture lines. There was mild inflammatory change in surrounding tissues of the fistula. Pathological examination revealed that the fistula was covered with the squamous epithelium, and had the muscularis mucosa. Her postoperative course was uneventful.

Aged↗

PubMed2001

Osteopontin-immunoreactivity in the rat trigeminal ganglion and trigeminal sensory nuclei.

Osteopontin-immunoreactivity (OPN-ir) was examined in the oro-facial tissues and trigeminal sensory nuclei (principal sensory nucleus and spinal trigeminal nucleus) to ascertain the peripheral ending and central projection of OPN-containing primary sensory neurons in the trigeminal ganglion (TG). No staining was observed using mouse monoclonal anti-OPN antibody preabsorbed with recombinant mature OPN. OPN-immunoreactive (ir) peripheral endings were classified into two types: encapsulated and unencapsulated types. Unencapsulated endings were subdivided into two types: simple and complex types. Simple endings were characterized by the thin neurite that was usually devoid of ramification. These endings were seen in the hard plate and gingiva. The complex type was characterized by the thick ramified neurite, and observed in the vibrissa, hard palate, and molar periodontal ligament. Encapsulated endings were found only in the hard palate. The trigeminal sensory nuclei contained OPN-ir cell bodies and neuropil. The neuropil was devoid of ir in laminae I and II of the medullary dorsal horn (MDH), and had various staining intensities in other regions of the trigeminal sensory nuclei. Transection of the infraorbital and inferior alveolar nerves caused an increase of OPN-ir intensity in ipsilateral TG neurons. The staining intensity of the neuropil also increased in the trigeminal sensory nuclei ipsilateral to the neurotomy excepting laminae I and II of the MDH. The present study indicates that OPN-ir primary sensory neurons in the TG innervate encapsulated and unencapsulated corpuscular endings. Such neurons probably project their central terminals to the trigeminal sensory nuclei except for the superficial laminae of the MDH.

Animals↗

PubMed2001

Amida predominantly expressed and developmentally regulated in rat testis.

Amida was first isolated from a rat hippocampal cDNA library as an Arc-associated protein. Previous studies showed that Amida is a nuclear protein and overexpression of Amida induces cell apoptosis. In this study, we found that Amida mRNA was expressed predominantly in rat testis by Northern blot analysis. During the development of testis, Amida mRNA was barely detectable until postnatal days 24 to 29 during which it increased to levels found in adults. However, Amida protein was not detected until postnatal day 32. Amida mRNA was found to be enriched in spermatocytes and less in round spermatids, but was undetectable in elongated spermatids by in situ hybridization. In addition, Amida protein was observed in the nucleus of spermatocytes and even in the elongated spermatids by immunohistochemistry. The development and cellular localization differences of Amida mRNA and protein implicates that Amida mRNA may undergo posttranscriptional regulation. Furthermore, Amida mRNA decreased significantly in the 8-day experimental cryptorchid testis when spermatogenesis was disrupted. Taken together, these data suggest that Amida is involved in spermatogenesis and may play an important role in development of testicular germ cells.

Animals↗

PubMed2001

VRL-1 immunoreactivity in the rat cranial autonomic ganglia.

Immunohistochemistry for VRL-1, a newly cloned capsaicin-receptor homologue, was performed on the rat cranial autonomic ganglia. The immunoreactivity (ir) was detected in the majority of neurones in the pterygopalatine (66%) and submandibular ganglia (68%). In the tongue and carotid body, parasympathetic neurones contained VRL-I ir. In the superior cervical ganglion, only 2% of postganglionic sympathetic neurones showed the immunoreactivity. VRL-1-ir nerve endings could not be detected in their peripheral tissues. These findings may suggest that VRL-1 has functions within neuronal cell bodies of the cranial autonomic ganglia.

Animals↗

PubMed2001

Developmental dependency of Merkel endings on trks in the palate.

Immunohistochemistry for protein gene product 9.5 was performed on Merkel cells in the palate of wildtype and knockout mice for trkA, trkB or trkC. In wildtype mice, numerous Merkel cells were observed at the top of anterior four rugae. In the posterior four rugae, Merkel cells were fewer and mostly located at the base of rugae. In knockout mice for trkA, trkB and trkC, Merkel cells at the top of rugae mostly disappeared although those at the base of rugae remained unchanged. Therefore, the number of Merkel cells in anterior four rugae decreased. In posterior four rugae, however, the number of Merkel cells in the mutant mice was similar to that for wildtype mice. Immunohistochemistry for S100 also demonstrated that the loss of genes for trkA, trkB and trkC caused the absence of the immunoreactive innervation of Merkel cells. The normal development of Merkel endings at the top of palatal rugae is probably dependent on trkA, trkB and trkC.

Animals↗

PubMed2001

Use of ion-exchange resins to prepare 100 microm-sized microcapsules with prolonged drug-release by the Wurster process.

Ion-exchange resin (IER)--drug complexes were used as core materials to explore their capability to prepare a 100 microm-sized, highly drug-incorporated microcapsule with a prolonged drug release by the Wurster process. Diclofenac sodium was loaded into Dowex 1-X2 fractionated into 200--400 mesh and subsequently microencapsulated with two types of aqueous colloidal polymer dispersion, Aquacoator Eudragit RS30D. The mass median diameter and drug content of the microcapsules thus obtained were 98 microm and 46% with Aquacoat, and 95 microm and 50% with Eudragit RS30D, respectively. Each microcapsule was obtained at a product yield of 94%. The rate of drug release from the microcapsules was highly dependent on the encapsulating materials. For the microcapsules coated with Aquacoat, diclofenac sodium was found to be rapidly released over 4 h, even at a 25 wt% coating level because of cracks on the microcapsule surfaces resulting from the swelling stress of the drug-loaded IER cores. In contrast, significantly prolonged drug-release was achieved in the microcapsules prepared with Eudragit RS30D: even such a very low coating level as 3 wt% provided an exceptionally prolonged drug-release over 24 h. The results indicated that the use of IER along with a flexible coating material would be a feasible way to prepare a prolonged release type of microcapsules with a diameter of 100 microm and a drug content of more than 50% by the Wurster process.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Anomalous temperature dependence of the magnetic field induced antiferromagnetic moment in the antiferroquadrupolar ordered state of CeB6.

The magnetic field induced antiferromagnetic moment M(AF) at low magnetic fields in the antiferroquadrupolar (AFQ) ordered phase of CeB6 was investigated by elastic neutron diffraction experiments for H parallel [110]. The peak intensity at the AF magnetic reciprocal point (1 / 2,1 / 2,1 / 2) corresponding to M(2)(AF) increases with decreasing temperature below the AFQ ordering temperature T(Q), and exhibits a broad maximum at T approximately 3 K and decreases with a further decrease of temperature. This unusual behavior of M(AF) at low fields is explained as a result of the competition between the AF-octupolar and AF-exchange interactions in the O(xy) type AFQ ordered state.

Journal Article↗

PubMed2001

Global effects of anchorage on gene expression during mammary carcinoma cell growth reveal role of tumor necrosis factor-related apoptosis-inducing ligand in anoikis.

Anchorage-independent growth is a hallmark of tumor cells. We compared gene expression profiles of anchored and nonanchored human mammary carcinoma cells to study this phenomenon. In this study, we show that anchorage had striking effects on cell growth and morphology but altered transcript levels from a limited number of genes. Only about 1% of mRNA transcripts detected in these cells was altered by anchorage. These include genes related to amino acid and polyamine metabolism, apoptosis, ion channels, cytoskeletal and stress proteins, transcription factors, and growth factors. Some of these may be crucial for the survival of transformed cells. For example, clusterin and the tumor necrosis factor-related apoptosis inducing ligand (TRAIL) were suppressed by anchorage, which could help prevent programmed cell death of these tumor cells. In addition to suppressing TRAIL expression, anchorage also decreased the susceptibility of these tumor cells to TRAIL-induced apoptosis as determined by poly(ADP-ribose) phosphorylase cleavage, annexin-V binding (P < 0.01), and cell cycle analysis (P < 0.0001). These data may help explain mechanisms by which anchorage prevents apoptosis of cells that would otherwise experience anoikis. Thus, genes found to be altered by this analysis could serve as potential targets for anticancer therapy. These findings suggest that TRAIL may be used as a means to target circulating epithelial tumor cells before their attachment and colonization at new sites.

Anoikis↗

PubMed2001

VR1-immunoreactive primary sensory neurons in the rat trigeminal ganglion.

Immunohistochemistry for VR1, a nociceptive transducer for vanilloid compounds, protons and heat (>43 degrees C), was performed on the rat trigeminal ganglion (TG). The immunoreactivity (IR) was detected in 20% of TG cells and these neurons were mostly small- to medium-sized (mean+/-S.D. 427+/-189 microm(2)). Twenty-six percent of the TG neurons retrogradely labeled from the facial skin exhibited VR1-IR, while the IR was detected in only 8% of those labeled from the tooth pulp. Co-expression of VR1 was common among the calcitonin gene-related peptide-immunoreactive cutaneous neurons (63%) but not among the similar tooth pulp neurons (20%). The present study indicates that primary nociceptive neurons which respond to vanilloid compounds, protons and heat are abundant in the facial skin but not in the tooth pulp.

Animals↗

PubMed2001

Peripheral neuroglial death induced by cisplatin administration in newborn rats.

To determine the target of cytotoxicity of cisplatin (CDDP), we injected newborn rats with 2 mg/kg CDDP and examined the trigeminal ganglion for possible cell death. A nick translation method for DNA fragmentation revealed CDDP-induced glial cell death. DNA fragmentation was detected in both Schwann cells and satellite cells. Satellite cell death was observed as early as 0.5 day after injection, most frequent at 1-3 days and subsided thereafter. The incidence of neuronal death was very low and comparable to that observed in vehicle control rats. CDDP has selective toxicity to peripheral glial cells, though the damage did not culminate in cell death in adults. The glial toxicity may contribute to clinical symptoms of CDDP neuropathy.

Animals↗

PubMed2001

Autoantibody to DNA excision repair enzyme hMYH in a patient with rheumatic disease.

We screened a human HepG2 cell cDNA expression library using serum from a patient with rheumatic disease. This serum had immunofluorescence reactivity to nuclei with a homogeneous staining pattern and to punctuate nuclear aggregates, chromosomal metaphase plate, midbody, and cytoplasmic bridge. YT1, the longest cDNA clone isolated, has sequence identity to hMYH, the human homologue of the Escherichia coli excision repair enzyme, DNA adenine glycosylase MutY. YT1 is a truncated cDNA of 1619 bp, encoding amino acids 22-535, and contains a full-length 3'-UTR sequence. We were unable to express a bacterial malE fusion protein incorporating amino acids 22 to 535 of hMYH. Consequently, we generated two additional malE fusion proteins of hMYH encoding amino acids 1-120 (pMAL-c2:hMYH(1-120)) and amino acids 121-535 (pMAL-c2:hMYH(121-535)). The patient serum immunoblotted only pMAL-c2:hMYH(1-120), suggesting that the autoepitope(s) is restricted to amino acids 22-120 of hMYH, and detected a protein of approximately 59-kDa in total HeLa and nuclear extracts consistent with reactivity to hMYH. Affinity-purified autoantibodies to pMAL-c2:hMYH(1-120) reacted by immunoblot to pMAL-c2:hMYH(1-120), with no reactivity to pMAL-c2:hMYH(121-535). By immunofluorescence, these antibodies displayed staining of nuclei. This is the first report of autoantibodies to hMYH in a patient with rheumatic disease. We were able to identify hMYH reactivity in relatively small cohorts of sera collected from rheumatoid factor-positive patients (6 of 18) and dsDNA-positive patients (1 of 18), with no reactivity detected in serum collected from 9 healthy subjects.

Autoantibodies↗

PubMed2001

Endobronchial metastasis of breast cancer 5 years after breast-conserving therapy.

A 42-year-old woman, who had received right breast-conserving therapy 5 years previously, was admitted with hemoptysis. Chest X-rays showed a tumor shadow in the left pulmonary hilus with partial atelectasis in the left lower lobe. Bronchofiberscopic examination showed a polypoid tumor arising from the endobronchial wall, with bleeding and a white surface coat. Although, microscopically, the tumor resembled the breast cancer resected previously, as we could not rule out primary lung carcinoma, and as the tumor seemed to be localized, thoracotomy was performed. During posterolateral thoracotomy, however, pleural metastatic nodules were found; therefore, only sampling of these nodules and the administration of 50 mg of cisplatin (CDDP) into the thoracic cavity were performed. From a comparison of the histopathological features of the original tumor and the intrathoracic tumor, and from the hormone receptor positivity of the pleural metastasis, we diagnosed the intrathoracic tumor as being highly suspicious of metastasis from breast cancer. The measurement of hormone receptor was informative for the diagnosis of and for selecting a therapeutic strategy for the metastatic breast cancer.

Adult↗