Jay J - Academia.edu (original) (raw)

Papers by Jay J

Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproduct... more Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproductive cycle and spawning with lunar cycle of the top shell, Trochus niloticus were investigated by histological examination. The specimens were sampled in the coastal waters of Chuuk Island, Micronesia, form November 1999 to September 2000. T. niloticus is a gonochorism, and the female and male were present in an approximately 1:1 ratio (p > 0.05). The ovary contained with the oocyte of yolk stage, the testis composed of the spermatid and spermatozoa at around the year. Monthly GBI were higher at February, March, April and June than the other months. Major spawning occurred between April and May, and June and July but the individuals of partially spawning were presented throughout the year. GBI with lunar cycle were higher at the full moon than the other lunar phase. These results suggest that the spawning occurred between the full moon and last quarter moon.

We cloned and sequenced the cDNA encoding the and subunits from the pituitary of the blacktip gro... more We cloned and sequenced the cDNA encoding the and subunits from the pituitary of the blacktip grouper Epinephelus fasciatus, which regulate vitellogenesis and maturation in vertebrates, to achieve stable and healthy gametes. The full-length cDNAs of and were 571 bp and 617 bp, encoding 120 amino acid (aa) and 147 aa proteins, respectively. The deduced amino acid sequences of and were highly homologous (68-97%) to those of other Perciformes; E. bruneus, Dicentrarchus labrax, Thunnus thynnus, and Pseudolabrus sieboldi. Phylogenetic analysis showed that the deduced and amino acid sequences were categorized as a distinct subunit in the family, and are closely related to the teleostei and , respectively. and mRNA exhibited high abundance in the pituitary gland and low in other brain areas, but were not present in peripheral tissues, as determined by RT-PCR.

2014 Sixth International Conference on Ubiquitous and Future Networks (ICUFN), 2014

Passively powered radio frequency identification (RFID) tags are devices powered via harvested ul... more Passively powered radio frequency identification (RFID) tags are devices powered via harvested ultra-high frequency (UHF) radiation emitted by a reader device. These devices are relegated to a form wireless barcode and also applications from simple product identification to more complex applications such as environment sensing. In this paper, we propose and implement a small-size low-power digital logic design for a baseband RFID tag and baseband modem. We will demonstrate a potential solution for security problems in EPCglobal Gen2 protocol by using a novel block cipher designed for low-power and area-constrained devices to encrypt and transmit sensor data.

Korean Journal of Materials Research, 2004

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Marine Genomics, 2014

The goldlined spinefoot, Siganus guttatus, is a lunar-synchronized spawner, which repeatedly rele... more The goldlined spinefoot, Siganus guttatus, is a lunar-synchronized spawner, which repeatedly releases gametes around the first quarter moon during the reproductive season. A previous study reported that manipulating moonlight brightness at night disrupted synchronized spawning, suggesting involvement of this natural light source in lunar synchronization. The present study examined whether the mRNA expression pattern of melatonin receptor subtypes MT1 and Mel1c in the pineal organ of the goldlined spinefoot is related to moonlight. Real-time quantitative polymerase chain reaction analysis revealed that the abundance of MT1 and Mel1c mRNA at midnight increased during the new moon phase and decreased during the full moon phase. Exposing fish to moonlight intensity during the full moon period resulted in a decrease in Mel1c mRNA abundance within 1h. Fluctuations in the melatonin receptor genes according to changes in the moon phase agreed with those of melatonin levels in the blood. These results indicate that periodic changes in cues from the moon influence melatonin receptor mRNA expression levels. The melatonin-melatonin receptor system may play a role in predicting the moon phase through changes in night brightness.

Journal of Pineal Research, 2006

Journal of Pineal Research, 2008

Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 2013

Melatonin synthesis in the pineal gland and retina shows a rhythmic fashion with high levels at n... more Melatonin synthesis in the pineal gland and retina shows a rhythmic fashion with high levels at night and is controlled by a rate-limiting enzyme, arylalkylamine N-acetyltransferase (AANAT). A previous study revealed that moonlight suppresses the plasma melatonin levels of the goldlined spinefoot (Siganus guttatus), which exhibits a lunar cycle in its reproductive activity and repeats gonadal development toward and spawning around the first quarter moon. Whether the retina of this species responds to moonlight is unknown. To clarify the photoperceptive ability of this species, we aimed to clone the full-length cDNA of Aanat1 (sgAanat1) from the retina and examine its transcriptional pattern under several daylight and moonlight regimes. The full-length sgAanat1 cDNA (1,038 bp) contained a reading frame encoding a protein of 225 amino acids, which was highly homologous to AANAT1 of other teleosts. Reverse transcription-polymerase chain reaction (PCR) analysis revealed that among the tissues tested, sgAanat1 fragments were expressed exclusively in the retina. Real-time quantitative PCR analysis revealed that sgAanat1 fluctuated with high abundance at night under light-dark cycle and at subjective night under constant darkness, but not under constant light. These results suggest that sgAanat1 is regulated by both the external light signal and internal clock system. The abundance of sgAanat1 in the retina was higher at the culmination time around new moon than full moon phase. Additionally, exposing fish to brightness around the full moon period suppressed sgAanat1 mRNA abundance. Thus, moonlight is perceived by fish and has an impact on melatonin fluctuation in the retina.

Journal of Comparative Physiology A, 2006

Ichthyological Research, 2006

... 2003). Siganus luridus, Siganus rivulatus, S. canaliculatus, and Siganus spinus spawn at or a... more ... 2003). Siganus luridus, Siganus rivulatus, S. canaliculatus, and Siganus spinus spawn at or around the new moon (Bryan et al., 1975; Hasse et al., 1977; Popper et al., 1979; Hoque et al., 1999; Harahap et al., 2001). The synchronous ...

General and Comparative Endocrinology, 2007

The golden rabbitfish Siganus guttatus is a reef fish with a restricted lunar-synchronized spawni... more The golden rabbitfish Siganus guttatus is a reef fish with a restricted lunar-synchronized spawning rhythmicity and releases gametes simultaneously around the first quarter moon period during the spawning season. In order to understand the molecular aspects of the "circa" rhythms in this species, the full-length melatonin receptor (MT1) cDNA was cloned, and its diurnal/circadian regulation was examined. The full-length MT1 cDNA (1257 bp) contained an open reading frame that encodes a protein of 350 amino acids; this protein is highly homologous to MT1 of nonmammalian species. A high expression of MT1 mRNA with a day-night difference was observed in the whole brain, retina, liver, and kidney. When diurnal variations in MT1 mRNA expression in the retina and whole brain were examined using real-time quantitative RT-PCR, an increase in the mRNA expression was observed during nighttime in both tissues under conditions of light/dark, constant darkness, and constant light. This suggests that MT1 mRNA expression is under circadian regulation. The expression of MT1 mRNA in the cultured pineal gland also showed diurnal variations with high expression levels during nighttime; this suggests that the increased expression level observed in the whole brain is partially of pineal origin. Alternation of light conditions in the pineal gland cultures resulted in the changes in melatonin release into the culture medium as well as MT1 mRNA expression in the pineal gland. The present results suggest that melatonin and its receptors play an important role in the exertion of daily and circadian variations in the neural tissues.

Gastrointestinal Endoscopy, 1999

Mini-detachable snare ligation for the treatment of esophageal varices Figure 2. B, Endoscopic vi... more Mini-detachable snare ligation for the treatment of esophageal varices Figure 2. B, Endoscopic views of detachable snare ligation. The targeted varix is completely ligated by detachable snare. The use of a multiple rubber band ligator, although generally effective and well tolerated, has certain limitations, including high cost, reduced visual field, and inadvertent band release. The use of mini-detachable snare ligation versus multiple band ligation was studied in 103 patients with recent or active esophageal variceal bleeding. The outcomes assessed were immediate hemostasis and rates of recurrent bleeding, eradication, and recurrence: 46 underwent minidetachable snare ligations and 57 underwent multiple band ligations. Among patients with active bleeding, hemostasis was achieved in 6 of 7 (86%) in the minidetachable snare ligation group and 11 of 13 (85%) in multiple band ligation group. Recurrent bleeding after initial treatment occurred in 2 of 46 (5.5%) in the mini-detachable snare ligation group and 3 of 57 (5.3%) in the multiple band ligation group. Esophageal varices were eradicated or reduced to grade I in 4.8-+ 2.1 and 4.5 + 1.9 sessions in the minidetachable snare ligation group and multiple band ligation groups, respectively. The recurrence rate was 5 of 46 (11%) and 6 of 57 (11%) in the mini-detachable snare ligation groups and multiple band ligation groups during a follow-up period of 6 and 16 months, respectively. No serious complication occurred in either group. The mini-detachable snare is a new device that provides safe and effective treatment for esophageal varices that is comparable to multiple band ligation.

Fisheries Science, 2011

Iodothyronine deiodinases play an important role in thyroid hormone regulation in vertebrates. Th... more Iodothyronine deiodinases play an important role in thyroid hormone regulation in vertebrates. The aim of this study was to clone type II (SgD2) and type III (SgD3) iodothyronine deiodinase cDNA from the goldlined spinefoot (Siganus guttatus) using 3 0 -and 5 0 -rapid amplification of cDNA ends and then to assess their expression patterns in the liver under several experimental conditions by using quantitative real-time PCR. SgD2 (1013 bp) and SgD3 (1492 bp) contained open reading frames of 810 and 804 bp and encoded 270 and 269 amino acids, respectively. They were characterized by an in-frame TGA codon that was considered to be selenocysteine. An abundance of SgD2 and SgD3 mRNA was expressed in several tissues, with an increase at 1200 hours and a decrease at 2400 hours. Food deprivation suppressed the expression of SgD2, but not SgD3. Higher SgD2 and SgD3 mRNA levels in the liver were found in fish reared at 25°C than in those reared at 20 and 30°C. These results suggest that exogenous factors influence the mRNA levels of iodothyronine deiodinase genes in the liver and that transcription of the genes in certain tissues is partially regulated in a circadian manner.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2011

The aim of this study was to determine the involvement of neurohypophysial hormones in the diurna... more The aim of this study was to determine the involvement of neurohypophysial hormones in the diurnal patterns of the threespot wrasse Halichoeres trimaculatus, which is common in coral reefs and exhibits daily behavioral periodicity. Prohormone cDNAs of the neurohypophysial peptides, arginine vasotocin (AVT) and isotocin (IT), were cloned by 3′-and 5′-rapid amplification of cDNA ends (RACE). The distribution and expression patterns of pro-AVT and -IT mRNAs in the brain were determined using reverse-transcription polymerase chain reaction (RT-PCR) and real-time quantitative PCR, respectively. The respective full-length cDNAs of pro-AVT and -IT were 945 and 755 bp in length, respectively. The deduced amino acid sequences for pro-AVT and pro-IT were 154 and 156 residues in length, respectively. Both pro-peptides contained a signal sequence followed by the respective hormones and neurophysin connected by a Gly-Lys-Arg bridge. Pro-AVT mRNA was detected only in the hypothalamus area, while pro-IT mRNA in the whole part of the brain. The relative abundance of pro-AVT and -IT mRNA varied according to time of day; it was significantly greater at 12:00 h than at 24:00 h. Following intraperitoneal administration of melatonin, pro-AVT mRNA abundance in the brain decreased, while pro-IT mRNA abundance remained unchanged. These results demonstrate that daily fluctuations of pro-AVT and pro-IT levels in the brain of threespot wrasse are differentially regulated.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2007

The golden rabbitfish, Siganus guttatus, is a reef fish exhibiting a restricted lunar-related rhy... more The golden rabbitfish, Siganus guttatus, is a reef fish exhibiting a restricted lunar-related rhythm in behavior and reproduction. Here, to understand the circadian rhythm of this lunar-synchronized spawner, a melatonin receptor subtype-Mel(1c)-was cloned. The full-length Mel(1c) melatonin receptor cDNA comprised 1747 bp with a single open reading frame (1062 bp) that encodes a 353-amino acid protein, which included 7 presumed transmembrane domains. Real-time PCR revealed high Mel(1c) mRNA expression in the retina and brain but not in the peripheral tissues. When the fish were reared under light/dark (LD 12:12) conditions, Mel(1c) mRNA in the retina and brain was expressed with daily variations and increased during nighttime. Similar variations were noted under constant conditions, suggesting that Mel(1c) mRNA expression is regulated by the circadian clock system. Daily variations of Mel(1c) mRNA expression with a peak at zeitgeber time (ZT) 12 were observed in the cultured pineal gland under LD 12:12. Exposure of the cultured pineal gland to light at ZT17 resulted in a decrease in Mel(1c) mRNA expression. When light was obstructed at ZT5, the opposite effect was obtained. These results suggest that light exerts certain effects on Mel(1c) mRNA expression directly or indirectly through melatonin actions.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2011

Type II iodothyronine deiodinase (D2) converts 3,5,3′,5′-tetraiodothyronine to 3,5,3′-triiodothyr... more Type II iodothyronine deiodinase (D2) converts 3,5,3′,5′-tetraiodothyronine to 3,5,3′-triiodothyronine and is involved in regulating thyroid hormone-dependent processes in various tissues. D2 mRNA expression in the mediobasal hypothalamus is affected by photoperiod, which influences reproductive processes in temperate birds and mammals. We examined whether D2 mRNA is expressed in the hypothalamus (located in the forebrain within the diencephalon area) and whether its abundance is affected by day length, temperature, or food availability in the tropical spinefoot, Siganus guttatus, which is endemic to tropical monsoon areas. The reverse transcription-polymerase chain reaction (RT-PCR) revealed that D2 mRNA is expressed in various brain regions. The abundance of hypothalamic D2 mRNA was higher at 12.00 h than at 06.00 h or 24.00 h. Rearing fish under constant dark conditions resulted in a decrease in D2 mRNA abundance during the subjective night. A single injection of melatonin lowered D2 mRNA abundance within 3 h. Collectively, it appears that hypothalamic D2 mRNA abundance is regulated by the circadian system and/or melatonin. No differences in D2 mRNA abundance were observed, when fish were reared at 20, 25, and 30°C. However, food deprivation stimulated D2 mRNA expression during the daytime. These results suggest that photoperiodic and nutritive conditions affect hypothalamic D2 mRNA expression in S. guttatus.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2010

The aim of the present study was to examine the involvement of cortisol on melatonin synthesis in... more The aim of the present study was to examine the involvement of cortisol on melatonin synthesis in the pineal organ of the Mozambique tilapia, Oreochromis mossambicus. The circulating levels of melatonin in this species exhibited daily variations with a decrease during the photophase (0600, 1200, and 1800 h) and an increase during the scotophase (0000 h), while cortisol levels peaked during the early photophase (0600 h). The pineal organ was cultured in vitro in the dark in the presence of cortisol mimicking either stressed (100 ng/mL) or resting (10 ng/mL) concentration in tilapia. High cortisol concentration significantly reduced the levels of melatonin secreted into the medium. In the fish reared under stressful conditions, the nocturnal circulating levels of cortisol increased significantly, while melatonin did not change significantly. We detected glucocorticoid receptor (GR) transcripts in the pineal organ and a quantitative real-time PCR revealed that this receptor mRNA abundance fluctuated diurnally, increasing at 0600, 1800, and 0000 h and decreasing at 1200 h. The GR mRNA abundance in the pineal organ was not altered either in vitro when the organ was cultured in the presence of 100 ng/mL cortisol or in vivo when the fish were reared under stressful conditions. On the basis of these findings, it is proposed that cortisol lowers melatonin synthesis in the pineal organ, while the role of GR signaling in this process remains to be established.

Chemosphere, 2007

While vitellogenesis in male fish is commonly used as a biomarker of xenoestrogen exposure, very ... more While vitellogenesis in male fish is commonly used as a biomarker of xenoestrogen exposure, very little is known about the impacts associated with this unusual protein synthesis in feral populations. To this end, a recent study showed elevated circulating vitellogenin (VTG) levels in male Mozambique tilapia (Oreochromis mossambicus) collected from the Aja but not Tengan Rivers in Okinawa, Japan. Here we investigated whether this unusual protein synthesis in male fish from the Aja River affect transcript abundance of estrogen (ER), androgen (AR) and glucocorticoid (GR) receptors in the liver, brain and testis. The detection of plasma VTG levels ( approximately 100 microg ml(-1)) in male tilapia confirmed xenoestrogenic exposure in the Aja, but not the Tengan River. This protein induction was not associated with any changes in the reproductive capacity as assessed by sperm mobility and testis histology in the Aja fish. Plasma levels of estradiol-17beta, 11-ketotestosterone and cortisol were not significantly different between fish from the two rivers. Quantitative real-time PCR revealed a significant reduction in transcript levels of ERalpha and ERbeta, GR and ARalpha but not ARbeta, in the livers of tilapia from the Aja compared with the Tengan River. There were no significant changes in any of the steroid receptor transcript levels in either the brain or testis between the two rivers. Overall, our results imply that xenoestrogen exposure and VTG synthesis may lead to disruption of liver responsiveness to sex steroids and glucocorticoid stimulation in feral male fish.

Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproduct... more Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproductive cycle and spawning with lunar cycle of the top shell, Trochus niloticus were investigated by histological examination. The specimens were sampled in the coastal waters of Chuuk Island, Micronesia, form November 1999 to September 2000. T. niloticus is a gonochorism, and the female and male were present in an approximately 1:1 ratio (p > 0.05). The ovary contained with the oocyte of yolk stage, the testis composed of the spermatid and spermatozoa at around the year. Monthly GBI were higher at February, March, April and June than the other months. Major spawning occurred between April and May, and June and July but the individuals of partially spawning were presented throughout the year. GBI with lunar cycle were higher at the full moon than the other lunar phase. These results suggest that the spawning occurred between the full moon and last quarter moon.

We cloned and sequenced the cDNA encoding the and subunits from the pituitary of the blacktip gro... more We cloned and sequenced the cDNA encoding the and subunits from the pituitary of the blacktip grouper Epinephelus fasciatus, which regulate vitellogenesis and maturation in vertebrates, to achieve stable and healthy gametes. The full-length cDNAs of and were 571 bp and 617 bp, encoding 120 amino acid (aa) and 147 aa proteins, respectively. The deduced amino acid sequences of and were highly homologous (68-97%) to those of other Perciformes; E. bruneus, Dicentrarchus labrax, Thunnus thynnus, and Pseudolabrus sieboldi. Phylogenetic analysis showed that the deduced and amino acid sequences were categorized as a distinct subunit in the family, and are closely related to the teleostei and , respectively. and mRNA exhibited high abundance in the pituitary gland and low in other brain areas, but were not present in peripheral tissues, as determined by RT-PCR.

2014 Sixth International Conference on Ubiquitous and Future Networks (ICUFN), 2014

Passively powered radio frequency identification (RFID) tags are devices powered via harvested ul... more Passively powered radio frequency identification (RFID) tags are devices powered via harvested ultra-high frequency (UHF) radiation emitted by a reader device. These devices are relegated to a form wireless barcode and also applications from simple product identification to more complex applications such as environment sensing. In this paper, we propose and implement a small-size low-power digital logic design for a baseband RFID tag and baseband modem. We will demonstrate a potential solution for security problems in EPCglobal Gen2 protocol by using a novel block cipher designed for low-power and area-constrained devices to encrypt and transmit sensor data.

Korean Journal of Materials Research, 2004

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Marine Genomics, 2014

The goldlined spinefoot, Siganus guttatus, is a lunar-synchronized spawner, which repeatedly rele... more The goldlined spinefoot, Siganus guttatus, is a lunar-synchronized spawner, which repeatedly releases gametes around the first quarter moon during the reproductive season. A previous study reported that manipulating moonlight brightness at night disrupted synchronized spawning, suggesting involvement of this natural light source in lunar synchronization. The present study examined whether the mRNA expression pattern of melatonin receptor subtypes MT1 and Mel1c in the pineal organ of the goldlined spinefoot is related to moonlight. Real-time quantitative polymerase chain reaction analysis revealed that the abundance of MT1 and Mel1c mRNA at midnight increased during the new moon phase and decreased during the full moon phase. Exposing fish to moonlight intensity during the full moon period resulted in a decrease in Mel1c mRNA abundance within 1h. Fluctuations in the melatonin receptor genes according to changes in the moon phase agreed with those of melatonin levels in the blood. These results indicate that periodic changes in cues from the moon influence melatonin receptor mRNA expression levels. The melatonin-melatonin receptor system may play a role in predicting the moon phase through changes in night brightness.

Journal of Pineal Research, 2006

Journal of Pineal Research, 2008

Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 2013

Melatonin synthesis in the pineal gland and retina shows a rhythmic fashion with high levels at n... more Melatonin synthesis in the pineal gland and retina shows a rhythmic fashion with high levels at night and is controlled by a rate-limiting enzyme, arylalkylamine N-acetyltransferase (AANAT). A previous study revealed that moonlight suppresses the plasma melatonin levels of the goldlined spinefoot (Siganus guttatus), which exhibits a lunar cycle in its reproductive activity and repeats gonadal development toward and spawning around the first quarter moon. Whether the retina of this species responds to moonlight is unknown. To clarify the photoperceptive ability of this species, we aimed to clone the full-length cDNA of Aanat1 (sgAanat1) from the retina and examine its transcriptional pattern under several daylight and moonlight regimes. The full-length sgAanat1 cDNA (1,038 bp) contained a reading frame encoding a protein of 225 amino acids, which was highly homologous to AANAT1 of other teleosts. Reverse transcription-polymerase chain reaction (PCR) analysis revealed that among the tissues tested, sgAanat1 fragments were expressed exclusively in the retina. Real-time quantitative PCR analysis revealed that sgAanat1 fluctuated with high abundance at night under light-dark cycle and at subjective night under constant darkness, but not under constant light. These results suggest that sgAanat1 is regulated by both the external light signal and internal clock system. The abundance of sgAanat1 in the retina was higher at the culmination time around new moon than full moon phase. Additionally, exposing fish to brightness around the full moon period suppressed sgAanat1 mRNA abundance. Thus, moonlight is perceived by fish and has an impact on melatonin fluctuation in the retina.

Journal of Comparative Physiology A, 2006

Ichthyological Research, 2006

... 2003). Siganus luridus, Siganus rivulatus, S. canaliculatus, and Siganus spinus spawn at or a... more ... 2003). Siganus luridus, Siganus rivulatus, S. canaliculatus, and Siganus spinus spawn at or around the new moon (Bryan et al., 1975; Hasse et al., 1977; Popper et al., 1979; Hoque et al., 1999; Harahap et al., 2001). The synchronous ...

General and Comparative Endocrinology, 2007

The golden rabbitfish Siganus guttatus is a reef fish with a restricted lunar-synchronized spawni... more The golden rabbitfish Siganus guttatus is a reef fish with a restricted lunar-synchronized spawning rhythmicity and releases gametes simultaneously around the first quarter moon period during the spawning season. In order to understand the molecular aspects of the "circa" rhythms in this species, the full-length melatonin receptor (MT1) cDNA was cloned, and its diurnal/circadian regulation was examined. The full-length MT1 cDNA (1257 bp) contained an open reading frame that encodes a protein of 350 amino acids; this protein is highly homologous to MT1 of nonmammalian species. A high expression of MT1 mRNA with a day-night difference was observed in the whole brain, retina, liver, and kidney. When diurnal variations in MT1 mRNA expression in the retina and whole brain were examined using real-time quantitative RT-PCR, an increase in the mRNA expression was observed during nighttime in both tissues under conditions of light/dark, constant darkness, and constant light. This suggests that MT1 mRNA expression is under circadian regulation. The expression of MT1 mRNA in the cultured pineal gland also showed diurnal variations with high expression levels during nighttime; this suggests that the increased expression level observed in the whole brain is partially of pineal origin. Alternation of light conditions in the pineal gland cultures resulted in the changes in melatonin release into the culture medium as well as MT1 mRNA expression in the pineal gland. The present results suggest that melatonin and its receptors play an important role in the exertion of daily and circadian variations in the neural tissues.

Gastrointestinal Endoscopy, 1999

Mini-detachable snare ligation for the treatment of esophageal varices Figure 2. B, Endoscopic vi... more Mini-detachable snare ligation for the treatment of esophageal varices Figure 2. B, Endoscopic views of detachable snare ligation. The targeted varix is completely ligated by detachable snare. The use of a multiple rubber band ligator, although generally effective and well tolerated, has certain limitations, including high cost, reduced visual field, and inadvertent band release. The use of mini-detachable snare ligation versus multiple band ligation was studied in 103 patients with recent or active esophageal variceal bleeding. The outcomes assessed were immediate hemostasis and rates of recurrent bleeding, eradication, and recurrence: 46 underwent minidetachable snare ligations and 57 underwent multiple band ligations. Among patients with active bleeding, hemostasis was achieved in 6 of 7 (86%) in the minidetachable snare ligation group and 11 of 13 (85%) in multiple band ligation group. Recurrent bleeding after initial treatment occurred in 2 of 46 (5.5%) in the mini-detachable snare ligation group and 3 of 57 (5.3%) in the multiple band ligation group. Esophageal varices were eradicated or reduced to grade I in 4.8-+ 2.1 and 4.5 + 1.9 sessions in the minidetachable snare ligation group and multiple band ligation groups, respectively. The recurrence rate was 5 of 46 (11%) and 6 of 57 (11%) in the mini-detachable snare ligation groups and multiple band ligation groups during a follow-up period of 6 and 16 months, respectively. No serious complication occurred in either group. The mini-detachable snare is a new device that provides safe and effective treatment for esophageal varices that is comparable to multiple band ligation.

Fisheries Science, 2011

Iodothyronine deiodinases play an important role in thyroid hormone regulation in vertebrates. Th... more Iodothyronine deiodinases play an important role in thyroid hormone regulation in vertebrates. The aim of this study was to clone type II (SgD2) and type III (SgD3) iodothyronine deiodinase cDNA from the goldlined spinefoot (Siganus guttatus) using 3 0 -and 5 0 -rapid amplification of cDNA ends and then to assess their expression patterns in the liver under several experimental conditions by using quantitative real-time PCR. SgD2 (1013 bp) and SgD3 (1492 bp) contained open reading frames of 810 and 804 bp and encoded 270 and 269 amino acids, respectively. They were characterized by an in-frame TGA codon that was considered to be selenocysteine. An abundance of SgD2 and SgD3 mRNA was expressed in several tissues, with an increase at 1200 hours and a decrease at 2400 hours. Food deprivation suppressed the expression of SgD2, but not SgD3. Higher SgD2 and SgD3 mRNA levels in the liver were found in fish reared at 25°C than in those reared at 20 and 30°C. These results suggest that exogenous factors influence the mRNA levels of iodothyronine deiodinase genes in the liver and that transcription of the genes in certain tissues is partially regulated in a circadian manner.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2011

The aim of this study was to determine the involvement of neurohypophysial hormones in the diurna... more The aim of this study was to determine the involvement of neurohypophysial hormones in the diurnal patterns of the threespot wrasse Halichoeres trimaculatus, which is common in coral reefs and exhibits daily behavioral periodicity. Prohormone cDNAs of the neurohypophysial peptides, arginine vasotocin (AVT) and isotocin (IT), were cloned by 3′-and 5′-rapid amplification of cDNA ends (RACE). The distribution and expression patterns of pro-AVT and -IT mRNAs in the brain were determined using reverse-transcription polymerase chain reaction (RT-PCR) and real-time quantitative PCR, respectively. The respective full-length cDNAs of pro-AVT and -IT were 945 and 755 bp in length, respectively. The deduced amino acid sequences for pro-AVT and pro-IT were 154 and 156 residues in length, respectively. Both pro-peptides contained a signal sequence followed by the respective hormones and neurophysin connected by a Gly-Lys-Arg bridge. Pro-AVT mRNA was detected only in the hypothalamus area, while pro-IT mRNA in the whole part of the brain. The relative abundance of pro-AVT and -IT mRNA varied according to time of day; it was significantly greater at 12:00 h than at 24:00 h. Following intraperitoneal administration of melatonin, pro-AVT mRNA abundance in the brain decreased, while pro-IT mRNA abundance remained unchanged. These results demonstrate that daily fluctuations of pro-AVT and pro-IT levels in the brain of threespot wrasse are differentially regulated.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2007

The golden rabbitfish, Siganus guttatus, is a reef fish exhibiting a restricted lunar-related rhy... more The golden rabbitfish, Siganus guttatus, is a reef fish exhibiting a restricted lunar-related rhythm in behavior and reproduction. Here, to understand the circadian rhythm of this lunar-synchronized spawner, a melatonin receptor subtype-Mel(1c)-was cloned. The full-length Mel(1c) melatonin receptor cDNA comprised 1747 bp with a single open reading frame (1062 bp) that encodes a 353-amino acid protein, which included 7 presumed transmembrane domains. Real-time PCR revealed high Mel(1c) mRNA expression in the retina and brain but not in the peripheral tissues. When the fish were reared under light/dark (LD 12:12) conditions, Mel(1c) mRNA in the retina and brain was expressed with daily variations and increased during nighttime. Similar variations were noted under constant conditions, suggesting that Mel(1c) mRNA expression is regulated by the circadian clock system. Daily variations of Mel(1c) mRNA expression with a peak at zeitgeber time (ZT) 12 were observed in the cultured pineal gland under LD 12:12. Exposure of the cultured pineal gland to light at ZT17 resulted in a decrease in Mel(1c) mRNA expression. When light was obstructed at ZT5, the opposite effect was obtained. These results suggest that light exerts certain effects on Mel(1c) mRNA expression directly or indirectly through melatonin actions.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2011

Type II iodothyronine deiodinase (D2) converts 3,5,3′,5′-tetraiodothyronine to 3,5,3′-triiodothyr... more Type II iodothyronine deiodinase (D2) converts 3,5,3′,5′-tetraiodothyronine to 3,5,3′-triiodothyronine and is involved in regulating thyroid hormone-dependent processes in various tissues. D2 mRNA expression in the mediobasal hypothalamus is affected by photoperiod, which influences reproductive processes in temperate birds and mammals. We examined whether D2 mRNA is expressed in the hypothalamus (located in the forebrain within the diencephalon area) and whether its abundance is affected by day length, temperature, or food availability in the tropical spinefoot, Siganus guttatus, which is endemic to tropical monsoon areas. The reverse transcription-polymerase chain reaction (RT-PCR) revealed that D2 mRNA is expressed in various brain regions. The abundance of hypothalamic D2 mRNA was higher at 12.00 h than at 06.00 h or 24.00 h. Rearing fish under constant dark conditions resulted in a decrease in D2 mRNA abundance during the subjective night. A single injection of melatonin lowered D2 mRNA abundance within 3 h. Collectively, it appears that hypothalamic D2 mRNA abundance is regulated by the circadian system and/or melatonin. No differences in D2 mRNA abundance were observed, when fish were reared at 20, 25, and 30°C. However, food deprivation stimulated D2 mRNA expression during the daytime. These results suggest that photoperiodic and nutritive conditions affect hypothalamic D2 mRNA expression in S. guttatus.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2010

The aim of the present study was to examine the involvement of cortisol on melatonin synthesis in... more The aim of the present study was to examine the involvement of cortisol on melatonin synthesis in the pineal organ of the Mozambique tilapia, Oreochromis mossambicus. The circulating levels of melatonin in this species exhibited daily variations with a decrease during the photophase (0600, 1200, and 1800 h) and an increase during the scotophase (0000 h), while cortisol levels peaked during the early photophase (0600 h). The pineal organ was cultured in vitro in the dark in the presence of cortisol mimicking either stressed (100 ng/mL) or resting (10 ng/mL) concentration in tilapia. High cortisol concentration significantly reduced the levels of melatonin secreted into the medium. In the fish reared under stressful conditions, the nocturnal circulating levels of cortisol increased significantly, while melatonin did not change significantly. We detected glucocorticoid receptor (GR) transcripts in the pineal organ and a quantitative real-time PCR revealed that this receptor mRNA abundance fluctuated diurnally, increasing at 0600, 1800, and 0000 h and decreasing at 1200 h. The GR mRNA abundance in the pineal organ was not altered either in vitro when the organ was cultured in the presence of 100 ng/mL cortisol or in vivo when the fish were reared under stressful conditions. On the basis of these findings, it is proposed that cortisol lowers melatonin synthesis in the pineal organ, while the role of GR signaling in this process remains to be established.

Chemosphere, 2007

While vitellogenesis in male fish is commonly used as a biomarker of xenoestrogen exposure, very ... more While vitellogenesis in male fish is commonly used as a biomarker of xenoestrogen exposure, very little is known about the impacts associated with this unusual protein synthesis in feral populations. To this end, a recent study showed elevated circulating vitellogenin (VTG) levels in male Mozambique tilapia (Oreochromis mossambicus) collected from the Aja but not Tengan Rivers in Okinawa, Japan. Here we investigated whether this unusual protein synthesis in male fish from the Aja River affect transcript abundance of estrogen (ER), androgen (AR) and glucocorticoid (GR) receptors in the liver, brain and testis. The detection of plasma VTG levels ( approximately 100 microg ml(-1)) in male tilapia confirmed xenoestrogenic exposure in the Aja, but not the Tengan River. This protein induction was not associated with any changes in the reproductive capacity as assessed by sperm mobility and testis histology in the Aja fish. Plasma levels of estradiol-17beta, 11-ketotestosterone and cortisol were not significantly different between fish from the two rivers. Quantitative real-time PCR revealed a significant reduction in transcript levels of ERalpha and ERbeta, GR and ARalpha but not ARbeta, in the livers of tilapia from the Aja compared with the Tengan River. There were no significant changes in any of the steroid receptor transcript levels in either the brain or testis between the two rivers. Overall, our results imply that xenoestrogen exposure and VTG synthesis may lead to disruption of liver responsiveness to sex steroids and glucocorticoid stimulation in feral male fish.