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Biomedical subjects

Takashi Okuda

Publications and source records attributed to Takashi Okuda.

At least 19 recordsLinked to original sources
PubMed2006

Pulmonary relapse of non-Hodgkin's lymphoma in bilateral upper lobes.

We describe a 68-year-old male patient with diffuse large B-cell lymphoma (DLBCL) who suffered from relapse in bilateral upper lobes of the lung. The patient presented with cough, weakness and fever. A bronchovascular-lymphangitis-like shadow was detected in the bilateral upper lobes on a chest roentgenogram. Although cytological and cytofluorometric examinations revealed no malignant cells in the bronchoalveolar lavage fluid, trans-bronchial lung biopsy (TBLB) showed involvement of DLBCL in the bronchial mucosa. Recurrent lymphoma tends to extend along the bronchovascular bundles, resulting in granulomatous consolidation that may mimic tuberculosis and is likely to involve the lower lobes. Thus, TBLB proved to be essential for the diagnosis of the lung involvement of non-Hodgkin's lymphoma (NHL).

Aged↗
PubMed2006

Dehydration-induced expression of LEA proteins in an anhydrobiotic chironomid.

Late embryogenesis abundant (LEA) proteins are associated with desiccation tolerance in anhydrobiotic organisms. The larvae of an African chironomid, Polypedilum vanderplanki, are able to withstand almost complete desiccation during which they enter a state of suspended animation. Here, we developed an EST database from desiccating larvae and isolated three cDNAs encoding proteins (PvLEA1, PvLEA2, and PvLEA3) with highly significant matches to Group 3 LEA proteins. Both mRNA and protein levels of all three examples were increased by dehydration stress imposed by either desiccation or hypersalinity, and one protein, PvLEA2, is likely to be post-translationally processed into smaller molecules. This first description of LEA protein genes in arthropods suggests that this protein family is widespread throughout invertebrate phyla, and that animals, plants, and microorganisms possess similar mechanisms for combating dehydration stress.

Animals↗
PubMed2006

Biological effects of anhydrobiosis in an African chironomid, Polypedilum vanderplanki on radiation tolerance.

PURPOSE: Anhydrobiotic organisms are known to have an extremely high tolerance against a range of stresses. However, the functional role of anhydrobiosis in radiation tolerance is poorly understood, especially in development following irradiation. The present study aims to evaluate effects of anhydrobiosis on radiation tolerance in an anhydrobiotic insect, Polypedilum vanderplanki. MATERIALS AND METHODS: Larval survival (48 h), anhydrobiotic ability, metamorphosis and reproduction after exposure to 1-9000 Gy of gamma-rays at the larval stage were compared between anhydrobiotic (dry) and normal (wet) phases. RESULTS: Wet larvae were killed in a dose-dependent manner at doses higher than 2000 Gy, and all died within 8 h after 4000 Gy exposure. In contrast, dry larvae survived even 5000 Gy, and some of them still tolerated 7000 Gy and were alive at 48 h after rehydration. Moreover, greater radiotolerance of dry larva, compared to wet ones, was demonstrated in terms of metamorphoses. However, anhydrobiosis did not protect against radiation damage in terms of producing viable offspring. CONCLUSION: These results indicate that anhydrobiosis enhances radiotolerance, resulting in increases of successful metamorphoses.

Animals↗
PubMed2006

Radiation tolerance in the tardigrade Milnesium tardigradum.

PURPOSE: Tardigrades are known to survive high doses of ionizing radiation. However, there have been no reports about radiation effects in tardigrades under culture conditions. In this study, we investigated tolerance of the tardigrade, Milnesium tardigradum, against gamma-rays and heavy ions by determining short-term or long-term survival, and reproductive ability after irradiation. MATERIALS AND METHODS: Hydrated and anhydrobiotic animals were exposed to gamma-rays (1000 - 7000 Gy) or heavy ions (1000 - 8000 Gy) to evaluate short-term survival at 2, 24 and 48 h post-irradiation. Long-term survival and reproduction were observed up to 31 days after irradiation with gamma-rays (1000 - 4000 Gy). RESULTS: At 48 h after irradiation, median lethal doses were 5000 Gy (gamma-rays) and 6200 Gy (heavy ions) in hydrated animals, and 4400 Gy (gamma-rays) and 5200 Gy (heavy ions) in anhydrobiotic ones. Gamma-irradiation shortened average life span in a dose-dependent manner both in hydrated and anhydrobiotic groups. No irradiated animals laid eggs with one exception in which a hydrated animal irradiated with 2000 Gy of gamma-rays laid 3 eggs, and those eggs failed to hatch, whereas eggs produced by non-irradiated animals hatched successfully. CONCLUSION: M. tardigradum survives high doses of ionizing radiation in both hydrated and anhydrobiotic states, but irradiation with >1000 Gy makes them sterile.

Animals↗
PubMed2006

Estimation of radiation tolerance to high LET heavy ions in an anhydrobiotic insect, Polypedilum vanderplanki.

PURPOSE: Anhydrobiotic larvae of Polypedilum vanderplanki are known to show an extremely high tolerance against a range of stresses. We have recently reported that this insect withstands exposure to high doses of gamma-rays (linear energy transfer [LET] 0.2 keV/microm). However, its tolerance against high LET radiation remains unknown. The aim of this study is to characterize the tolerance to high-LET radiations of P. vanderplanki. MATERIALS AND METHODS: Larval survival and subsequent metamorphoses were compared between anhydrobiotic (dry) and non-anhydrobiotic (wet) samples after exposure to 1 - 7000 Gy of three types of heavy ions delivered from the azimuthally varying field (AVF) cyclotron with LET values ranging from 16.2 - 321 keV/microm. The tolerance against 4He ions was also compared among three chironomid species. RESULTS: At all LET values measured, dry larvae consistently showed greater radiation tolerance than hydrated larvae, perhaps due to the presence of high concentrations of the disaccharide trehalose in anhydrobiotic animals, and the radiation-induced damage became evident at lower doses as development progressed. Relative biological effectiveness (RBE) values based on the median inhibitory doses reached a maximum at 116 keV/microm (12C), and the maximum RBE clearly increased as development progressed. Lower D0 (dose to reduce survival from relative value 1.00 - 0.37 on the exponential part of the survival curve), and higher Dq (quasi-threshold dose) were found in individuals exposed to 4He ions, compared to gamma-rays, and in P. vanderplanki larvae compared to non-anhydrobiotic chironomids. CONCLUSION: Anhydrobiosis potentiates radiation tolerance in terms of larval survival, pupation and adult emergence of P. vanderplanki exposed to high-LET radiations as well as to low-LET radiation. P. vanderplanki larvae might have more efficient DNA damage repair after radiation than other chironomid species.

Animals↗
PubMed2005

Recurrent chromosomal rearrangements at bands 8q24 and 11q13 in gastric cancer as detected by multicolor spectral karyotyping.

AIM: To identify chromosomal translocations specific to gastric cancer (GC), spectral karyotyping (SKY) analysis was performed on established cell lines and cancerous ascitic fluids. METHODS: SKY analysis of 10 established cell lines and seven cancerous ascitic fluid samples identified recurrent chromosomal breakpoints and translocations in GC, several of which involved chromosomal loci of oncogenes or tumor suppressor genes. RESULTS: A total of 630 chromosomal breaks were identified. Chromosome no.8 was the most frequently involved in rearrangements (65 breaks), followed by chromosomes no.11 (53), no. 1 (49), no. 7 (46), no. 13 (37), no. 3 (36), no. 17 (33), and no. 20 (29). Frequent breakpoints were detected in 8q24.1 (30 breaks), 11q13 (29), 13q14 (16), 20q11.2 (14), 7q32 (13), 17q11.2 (13), 18q21 (12), 17q23 (9), 18q11.2 (9). SKY analysis identified a total of 242 chromosomal rearrangements including 190 reciprocal and non-reciprocal translocations. The recurrent combinations of chromosomal bands involved in translocations were 8q24.1 and 13q14 (3 cases), 8q24.1 and 11q13 (3), 11q13 and 17q11.2 (2), and 18q11.2 and 20q11.2 (2). Our study validated the ability of SKY to characterize in detail the chromosomal rearrangements in solid tumors and derived cell lines. Moreover, fluorescence in situ hybridization helped to identify the insertions, translocations, and homogeneously staining regions of MYC and CCND1 gene loci. CONCLUSION: The non-random co-localization of certain cytogenetic bands suggests the importance of chromosomal translocations in gastric carcinogenesis, by serving as landmarks for the cloning of GC causing genes.

Cell Line, Tumor↗
PubMed2005

Small bowel non-Hodgkin's lymphoma remaining in complete remission by surgical resection and adjuvant rituximab therapy.

A 44-year-old man was referred to our hospital with intermittent abdominal pain. Because distention of fluid- and gas-filled loops of small intestine was proved by X-ray, the patient was diagnosed as having small bowel obstruction. A laparotomy revealed a segmental stenosis in the jejunum, which showed diffuse thickening of the intestinal wall. Some mesenteric lymph nodes were swollen. Pathological examination was defined. We diagnosed diffuse large B-cell lymphoma based on the pathological findings of diffuse transmural infiltration of large lymphoid cells and flow-cytometric analyses. Rituximab was administered as adjuvant therapy at weekly doses of 375 mg/m2. Four cycles were performed every 6 mo and he remained CR. Rituximab may be effective as adjuvant therapy.

Adult↗
PubMed2005

Successful endoscopic hemostasis for gastric arterial bleeding due to invasion of malignant lymphoma.

A 75-year-old male with malignant lymphoma (ML) accompanied with gastric lesion was treated with combination chemotherapy. The patient produced tarry stool on the 4th d, and emergency gastroscopy showed arterial bleeding from the lesion. Hemostasis was achieved by injecting pure ethanol and using hemostatic clips. There is only one previous report on endoscopic hemostasis being effective for bleeding due to lymphoma. Since gastric bleeding causes significant mortality, endoscopic hemostasis should be considered as first-line treatment for ML patients who were treated with chemotherapy.

Aged↗
PubMed2005

Pseudomembranous colitis presenting as acute colonic obstruction without diarrhea in a patient with gastric Burkitt lymphoma.

Pseudomembranous colitis (PMC) usually manifests as fever and diarrhea in hospitalized patients treated with systemic antibiotics. We described a case of PMC with intestinal obstruction but without diarrhea. A 60-year-old man was hospitalized for chemotherapy for the treatment of Burkitt lymphoma of the stomach. The patient became febrile and complained of crampy abdominal pain during the post-chemotherapy nadir. Plain abdominal radiography showed some intestinal gas and niveau. Because stool cytotoxin assay for clostridium difficile was positive and colon fiberscopic examination showed a pseudomembrane at the left side of the colon, and a diagnosis of PMC was made. Treatment with intracolonic vancomycin administration by colonoscopy and nasoileus tube was successful. Physicians should take into account the possibility of bowel obstruction due to PMC occurring in patients undergoing chemotherapy and perform emergency colonoscopy examination of suspected cases.

Acute Disease↗
PubMed2005

An additional segment at 1p36 derived from der(18)t(14;18) in patients with diffuse large B-cell lymphomas transformed from follicular lymphoma.

The particular translocation in follicular lymphomas (FLs) is a t(14;18)(q32;q21), recombining the immunoglobulin heavy chain (IgH) gene on chromosome 14 with the B-cell leukemia/lymphoma 2 (BCL2) gene on chromosome 18. Some low-grade FLs are aggressively transformed into diffuse large B-cell lymphomas, presumably by acquisition of secondary chromosomal changes, including chromosomal band 1p36. A common example is add(1)(p36). Because it is difficult to identify the origin of add(1)(p36) even on high-resolution G-banding analysis, we used spectral karyotyping (SKY) and double-color fluorescence in situ hybridization (DC-FISH) to define the t(14;18) and the extra band at 1p36 in two cases of diffuse large B-cell lymphoma (DLBCL). SKY revealed that the extra chromosomal segment on 1p36 was derived from chromosome 18. DC-FISH defined BCL2/IgH fusion signals at 1p36 in addition to t(14;18), suggesting that BCL2/IgH fusion at 1p36 was an evolutionary alteration following the primary BCL2/IgH translocation on der(18) in both cases. Our results indicate that IgH alleles, implicated in chromosomal rearrangement, may themselves frequently be targets for secondary translocations, suggesting that multiple IgH translocations and insertions are associated with the progression of FL.

Chromosome Banding↗
PubMed2005

Molecular cloning and analysis of a novel teratocyte-specific carboxylesterase from the parasitic wasp, Dinocampus coccinellae.

Teratocytes derived from the embryonic membrane (serosa) of parasitoids are released into the host hemocoel when the parasitoid eggs hatch, where they perform several functions during the post-embryonic stage. A full-length cDNA encoding a putative carboxylesterase was isolated from the teratocytes of Dinocampus coccinellae and was designated as teratocyte-specific carboxylesterase (TSC). It contained an open reading frame of 2571 bp coding for a protein of 857 amino acids with a calculated molecular mass of 89 kDa. The deduced amino acid sequence had many structural features that are highly conserved among serine hydrolases including Ser, Glu and His as a catalytic triad, carboxylesterase type-B (FGGNPNSVTLLGYSAG)/ lipase-serine (VTLLGYSAGA) active sites, and six N-glycosylation sites. Interestingly, the mRNA encoding the TSC gene was expressed exclusively in teratocytes but not in the parasitoid larva or in the non-parasitized host. Most notably, the TSC protein was distinguished by an insertion of 294 amino acids towards the N-terminal region and was flanked by carboxylesterase domains. Furthermore, sequence alignment and homology search revealed these additional amino acids to be unique to TSC and the insertion contributed significantly to its molecular mass resulting in a larger protein than other esterases. In addition to sequence analysis, the possible role of TSC in relation to the host (Coccinella septempunctata) and parasitoid (D. coccinellae) system is discussed.

Amino Acid Sequence↗
PubMed2005

Induction of anhydrobiosis in fat body tissue from an insect.

The larva of the African chironomid Polypedilum vanderplanki can withstand complete desiccation. Our previous reports revealed that even when the larva is dehydrated without a brain, it accumulated a great amount of trehalose and successfully went into anhydrobiosis. In this paper we determined the viability after rehydration in tissues from the larvae followed by complete dehydration. Only fat-body tissues that were the main producer of trehalose could be preserved in a dry state at room temperature for an extended period of more than 18 months in a viable form. Thus we have confirmed that the central nervous system is not involved in the induction of anhydrobiosis, even in this complex multicellular organism.

Animals↗
PubMed2004

Ultrastructural localization of high-affinity choline transporter in the rat neuromuscular junction: enrichment on synaptic vesicles.

In cholinergic neurons, Na(+)- and Cl(-)-dependent, hemicholinium-3-sensitive, high-affinity choline uptake system is thought to be the rate-limiting step in acetylcholine (ACh) synthesis. The system is highly regulated by neuronal activity; the choline uptake is increased by a condition in which ACh release is favored. Here we analyzed the ultrastructural localization of the high-affinity choline transporter (CHT) in the rat neuromuscular junctions with two separate antibodies. The majority (>90%) of immunogold labeling of CHT was observed on synaptic vesicles rather than the presynaptic plasma membrane. Less than 5% of the gold-silver particles were associated with the plasma membrane, and more than 70% of such particles were localized within or in close vicinity to presynaptic active zones. Our morphological data support the recent hypothesis that trafficking of CHT from synaptic vesicles to the plasma membrane couples neuronal activity and choline uptake.

Animals↗
PubMed2003

Detection of the high-affinity choline transporter in the MOLT-3 human leukemic T-cell line.

We previously showed that lymphocytes possess the necessary components to constitute an independent, non-neuronal cholinergic system; these include acetylcholine (ACh) itself, choline acetyltransferase (the ACh-synthesizing enzyme), and both muscarinic and nicotinic ACh receptors (AChRs). In addition, we showed that stimulation of AChRs with their respective agonists elicits a variety of biochemical and functional effects, suggesting that lymphocytic cholinergic system is involved in the regulation of immune function. In nerve terminals, choline taken up via the high-affinity choline transporter (CHT1) is exclusively utilized for ACh synthesis. In the present study, therefore, we investigated the expression of CHT1 in T-lymphocytes. Reverse transcription-polymerase chain reaction analysis revealed that MOLT-3 cells, a human leukemic T-cell line used as a T-lymphocyte model, expressed CHT1 mRNA, but that the CEM and Jurkat T-cell lines did not. Consistent with that finding, specific binding of [3H]hemicholinium-3 (HC-3), an inhibitor of CHT1, and HC-3-sensitive [3H]choline uptake were also detected in MOLT-3 cells. These results suggest that CHT1 plays a role in mediating choline uptake in T-lymphocytes and provides further evidence for the presence of an independent lymphocytic cholinergic system.

Cell Line↗
PubMed2003

High-affinity choline transporter.

The cholinergic neurons have long been a model for biochemical studies of neurotransmission. The components responsible for cholinergic neurotransmission, such as choline acetyltransferase, vesicular acetylcholine transporter, nicotinic and muscarinic acetylcholine receptors, and acetylcholine esterase, have long been defined as functional units and then identified as molecular entities. Another essential component in the cholinergic synapses is the one responsible for choline uptake from the synaptic cleft, which is thought to be the rate-limiting step in acetylcholine synthesis. A choline uptake system with a high affinity for choline has long been assumed to be present in cholinergic neurons. Very recently, the molecular entity for the high-affinity choline transporter was identified and is designated CHT1. CHT1 mediates Na(+)- and Cl(-)-dependent choline uptake with high sensitivity to hemicholinium-3. CHT1 has been characterized both at the molecular and functional levels and was confirmed to be specifically expressed in cholinergic neurons.

Amino Acid Sequence↗
PubMed2003

Increase of internal ion concentration triggers trehalose synthesis associated with cryptobiosis in larvae of Polypedilum vanderplanki.

Larvae of an African chironomid, Polypedilum vanderplanki, which live in temporal rock pools, are completely dehydrated when the pools dry up and undergo anhydrobiosis until the next rain comes. During the dehydration process, larvae accumulate large amounts of trehalose, which provides effective protection against desiccation because of its high capacity for water replacement and vitrification. As the occurrence of rapid trehalose synthesis coincides with loss of body water, changes of osmolarity in the body are thought to be a cue for trehalose synthesis. Indeed, exposure to high salinity triggers rapid and efficient accumulation of trehalose even without desiccation treatment. As this rapid production occurs mainly in high concentrations of salt solutions, we conclude that an increase in internal ion concentration triggers trehalose synthesis associated with cryptobiosis in this species.

Animals↗
PubMed2003

Juvenile hormone biosynthesis in diapause and nondiapause females of the adult blow fly Protophormia terraenovae.

In vitro synthetic activities of juvenile hormones (JH) were examined using a radiochemical assay in diapause females and reproductive females of the blow fly, Protophormia terraenovae. Thin layer chromatography showed that products of the corpus allatum (CA) comigrated with a synthetic sample of JH III bisepoxide but neither with JH III nor methylfarnesoate. JH synthetic activities increased in females reared under LD 18:6 at 25 degrees C, as the ovaries developed. The synthetic activities remained low in previtellogenic females reared under LD 12:12 at 20 degrees C. Removal of the pars intercerebralis completely prevented ovaries from development under reproductive conditions, and removal of the pars lateralis caused partial or full development of ovaries under diapause-inducing conditions. In these operated animals, the JH synthetic activities were not significantly different from those of the intact and sham-operated animals. The results indicate that the CA in P. terraenovae produces mainly JH III bisepoxide and a decrease in the JH production rate is a cause of diapause induction. PI neurons and PL neurons in the brain do not directly mediate changes in the JH production rate, but regulate ovarian development cooperatively with some unknown allatostatic and allatotropic factors.

Animals↗