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K Aida

Publications and source records attributed to K Aida.

At least 73 records · Page 4Linked to original sources
PubMed1997

Molecular cloning of cDNA encoding two types of pituitary gonadotropin alpha subunit from the goldfish, Carassius auratus.

Two types of cDNA encoding the alpha subunit of pituitary gonadotropin (GTH) were cloned by polymerase chain reaction (PCR) for goldfish pituitary cDNA library. The goldfish GTH-alpha subunit cDNAs, designated as alpha 1 and alpha 2, encode 117 and 118 amino acids, respectively, including a 23-amino-acid signal peptide. These two types of cDNAs showed high homology in nucleotide and amino acid sequence, but deletion of a triplet nucleotides was present in alpha 1. Deduced amino acid sequences represented differences in four residues between alpha 1 and alpha 2 subunits. Analyses of goldfish genomic DNA revealed that each individual goldfish possesses two distinct genes relevant to GTH-alpha 1 and -alpha 2 subunits. Results of reverse transcriptase-PCR analysis suggest that these two GTH-alpha subunit genes are expressed at different levels without relation to sex and gonadal maturity.

Amino Acid Sequence↗
PubMed1997

Characterization, guanosine 5'-O-(3-thiotriphosphate) modulation, daily variation, and localization of melatonin-binding sites in the catfish (Silurus asotus) brain.

Characteristics, guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) modulation, daily variation, and localization of melatonin-binding sites in the brain of a nocturnal teleost, the catfish Silurus asotus, were studied by radioreceptor assay using 2-[125I]iodomelatonin as the radioligand. The specific binding was rapid, stable, saturable, and reversible. The radioligand binds to a single class of receptor site with an affinity (Kd) of 30.7 +/- 7.3 pM and total binding capacity (Bmax) of 9.76 +/- 0.79 fmol/mg protein (mean +/- SE, n = 5). The binding sites were highly specific for 2-iodomelatonin and melatonin. The specificity was almost identical to that of functional melatonin receptors in the dermal and epidermal melanophores in this species and that of ML-1 subtype melatonin receptors in vertebrates, including melatonin-binding sites in the goldfish brain. GTPgammaS treatment altered both the Kd and Bmax values, indicating that melatonin-binding sites in the catfish brain are coupled to G protein. The Bmax values exhibited no daily variation under light-dark cycles of 12 hr light:12 hr dark whereas plasma melatonin levels and Kd fluctuated in a rhythmic fashion. The density of melatonin-binding sites in discrete brain areas was determined to be highest in optic tectum-thalamus and hypothalamus, intermediate in telencephalon, cerebellum, and medulla oblongata, and lowest in olfactory bulbs. These results suggest that melatonin secreted from the pineal organ and/or retina plays neuromodulatory roles in the catfish brain via G protein-coupled melatonin receptors. Characteristics of melatonin receptors seem to be highly conserved during evolution, although the density of melatonin receptors is not regulated by melatonin itself in this species.

Animals↗
PubMed1997

Induction of male-type gonadotropin secretion by implantation of 11-ketotestosterone in female goldfish.

In goldfish, plasma gonadotropin levels increase during spawning in both males and females (GTH surge). A female-typical GTH surge induces ovulation (ovulatory surge), and a male-typical surge triggers milt production in response to sex pheromones released from ovulatory females. This study examined whether the male-typical GTH surge occurs in adult females that are implanted with 11-ketotestosterone (KT), which induces male-typical sexual behavior in adult female goldfish. When KT-implanted females were exposed to ovulatory females, a GTH surge occurred without ovulation. No GTH surge was observed when KT-females were exposed to nonovulatory females. The GTH secretion in KT-females was further characterized by exposure to 17alpha,20beta-dihydroxy-4-pregnen-3-one (17,20-P), a female sex pheromone that induces the GTH surge in males. Exposure to waterborne 17,20-P caused an elevation of GTH levels in KT-females as well as in males. The elevation of GTH levels induced by 17,20-P exposure was abolished when the KT-females were rendered anosmic. Unlike the female-typical ovulatory GTH surge that occurs in synchrony with photoperiod and peaks in the dark phase of the day, the 17,20-P-induced surge did not show a peak in the dark phase. These results indicate that the GTH surge in KT-females is a male-typical surge. Together with a previous study showing KT-induced behavioral masculinization (N. E. Stacey and M. Kobayashi, 1996, Horm. Behav. 30, 434-445), this adult gonochoristic species was shown to possess sexual plasticity of brain function in behavior and GTH secretion in response to sex steroid.

Animals↗
PubMed1997

Steroid hormone-dependent overexpression of cytochromes P450 2A in liver tumors of TGF alpha transgenic male mice.

To clarify the mechanism underlying the male preference of liver tumor in transforming growth factor (TGF) alpha transgenic mice, we analyzed the sexually dimorphic expression of two P450s, i.e., female-specific mouse 15 alpha hydroxylase P450 (2A4) and coumarin 7-hydroxylase P450 (2A5). The expression of 2A4 mRNA in the livers of both transgenic and nontransgenic males was low compared with that in females. P450 2A5 mRNA in the transgenic males was slightly elevated in the adjacent non-tumorous tissues and dramatically elevated in the tumor compared with that in nontransgenic male liver. The activity of P450 2A5 was higher in females than in males in control and transgenic mice but the difference was smaller in the transgenic mice. The activity of P450 2A5 was exceptionally high in liver tumors of transgenic males, as indicated by mRNA expression. These results suggest that female-specific P450 2A5 is induced in the livers of TGF alpha transgenic male mice, particularly in liver tumors of transgenic male mice overexpressing TGF alpha, and may be useful as a marker for mouse hepatocarcinogenesis.

Animals↗
PubMed1997

Amino acid sequences and activities of multiple hyperglycemic hormones from the Kuruma prawn, Penaeus japonicus.

By means of a single-step reversed-phase HPLC, six CHH family peptides were isolated from sinus gland extracts of the kuruma prawn, Penaeus japonicus. Five of these peptides (Pej-SGP-I, -II, -III, -V, and -VI) expressed hyperglycemic activity and were considered to be the hyperglycemic hormones of this prawn. The amino acid sequences of the five peptides were determined (the amino acid sequence of Pej-SGP-III had been previously determined), revealing that all consisted of 72 amino acid residues with a free amino-terminus and an amidated carboxyl-terminus. They showed considerable sequence similarity to one another, but much less similarity to Pej-SGP-IV with molt-inhibiting activity, the sequence of which had also been determined previously. Examination of the dose-response relationship of these peptides showed that they were equally potent but had different efficacies, which were in the order of Pej-SGP-V, -VI > -III, -I > -II, corresponding well with their sequence characteristics.

Amino Acid Sequence↗
PubMed1997

Transcriptional regulation by HNF-4 of the steroid 15alpha-hydroxylase P450 (Cyp2a-4) gene in mouse liver.

The mouse P450 gene Cyp2a-4 encodes the hepatic steroid 15apha-hydroxylase. We have defined in the 5'-flanking sequence of Cyp2a-4 gene, a composite regulatory element (-61AGACCAAAGTCCGGCCTTC-42) which contains a potential CpG methylation site at position -50. Gel-shift assays indicate that this element consists of overlapped binding sites for a hepatocyte-enriched transcription factor HNF-4 and a Sp1-like protein. Moreover, transcription of the Cyp2a-4 gene is activated by coexpression of HNF-4 in HepG2 cells. A mutation (C at -50 to A) abolishes the binding of HNF-4 to the element as well as the transcriptional activation by HNF-4. The methylated C at position -50, however, does not affect HNF-4 binding. Neither the mutation nor the methylation at position -50 affect the binding of Sp1-like protein to the element. It appears, therefore, that HNF-4 activates the hepatic transcription of Cyp2a-4 gene through its direct binding to the regulatory element regardless of the methylation at position -50.

Animals↗
PubMed1997

Mouse glycine N-methyltransferase is sexually dimorphic and regulated by growth hormone.

The secretion pattern of putuitary growth hormone (GH) in rodents is sexually dimorphic and regulates the expression of some hepatic genes. We report cloning of mouse glycine N-methyltransferase (GNMT) cDNA. The mouse GNMT mRNA is expressed at much lower levels in male than in female livers. Hypophysectomy in male mice resulted in as a high level of the expression as in female mice. Treatment with GH of hypophysectomized male mice twice a day for 5 days decreased the expression. These results indicate that the sex difference of the mouse GNMT expression is regulated by GH secretion patterns.

Amino Acid Sequence↗
PubMed1997

Ocular melatonin rhythms in the goldfish, Carassius auratus.

Ocular melatonin rhythms in the goldfish were studied and compared to those in the pineal organ and plasma. Under light:dark (LD) of 12 h light:12 h dark, melatonin contents in the eye as well as the pineal organ and plasma exhibited clear day-night changes with higher levels at mid-dark than at mid-light. However, melatonin contents in the eye at mid-light and mid-dark were approximately 100 and 9 times greater than those in the pineal organ, respectively. Day-night changes of ocular melatonin persisted after pinealectomy, which abolished those in plasma melatonin under LD 12:12. Ocular melatonin contents in the pinealectomized fish at mid-light were significantly higher than those in the sham-operated control. Under constant darkness (DD), circadian melatonin rhythms were observed in the eye but damped on the 3rd day, whereas plasma melatonin rhythms generated by the pineal organ persisted for at least 3 days. Under constant light, ocular melatonin contents exhibited a significant fluctuation with a smaller amplitude than that under DD, whereas plasma melatonin remained at low levels. These results indicate the involvement of LD cycles, a circadian clock, and the pineal organ in the regulation of ocular melatonin rhythms in the goldfish.

Animals↗
PubMed1997

Hesperidin as an inhibitor of lipases from porcine pancreas and Pseudomonas.

In the course of our screening work for new types of lipase inhibitors, hesperidin was identified as a simple and small molecular weight inhibitor in the peels of Citrus unshiu. Hesperidin inhibited lipase activity from porcine pancreas and that from Pseudomonas, and their IC50 was 32 and 132 micrograms/ml, respectively. Hesperidin, neohesperidin, narirutin, and naringin are known as the main flavonoids in Citrus unshiu. Neohesperidin also inhibited the lipase from procine pancreas, but did not have any effect on Pseudomonas. Narirutin and naringin did not show this effect on lipases from porcine pancreas and Pseudomonas. In animal experiments, the concentration of plasma triglyceride in rats fed a diet containing 10% hesperidin were significantly lower than that fed the control diet.

Animal Feed↗
PubMed1997

[Predisposition of subclones of pancreatic carcinoma cells, AsPC-1, to changes in functional and histopathological features of xenograft tumors with response to extracellular matrix].

We cloned two characteristics subclones from a human pancreatic carcinoma cell line, AsPC-1, according to their distinctive cell shapes; one an epithelial morphology and designated as "Beto-1" and the other a fibroblastic morphology and designated as "Fib-1". Fib-1 grew faster than Beto-1, but the growth rate of the cells on plastics was as high as that of the cells on the extracellular matrix extracts, matrigel. The pancreatic tumor-marker proteins, alpha-amylase, insulin, CEA, POA, PP, and AFP, but not CA 19-9, were positive in both subclones. Type IV collagen, fibronectin, and laminin, were all positive in both subclones; furthermore, the integrin adhesion receptor molecules, alpha 2 beta 1-subunit, alpha 5-subunit, and alpha 6-subunit, were also positive. The intercellular adhesion molecules, E-cadherin and ICAM-1, were detected in Beto-1 and Fib-1, respectively. Although both subclonal cells attached to type IV collagen, fibronectin, and laminin in a concentration-dependent manner. Beto-1 adhered most strongly to type IV collagen and Fib-1 attached most strongly to fibronectin. Beto-1 showed morphological differentiation on matrigel and in the tumor xenografts. Further, there was more fibroblast infiltration and type IV collagen production in Beto-1 tumor tissues, and more lymphocyte and neutrophil infiltration in tumors of Fib-1 which expressed ICAM-1 proteins. This study indicated that the histological diversity observed in the pancreatic carcinoma was evolved from the composition of the tumor cells which express the specific adhesion receptors.

Animals↗
PubMed1997

Molecular cloning of a molt-inhibiting hormone cDNA from the kuruma prawn Penaeus japonicus.

The crustacean molt-inhibiting hormone (MIH) is released from the X-organ sinus gland complex and suppresses ecdysteroid synthesis by the Y-organ. In the present study, we have isolated a cDNA which encodes a MIH (Pej-SGP-IV) of the kuruma prawn Penaeus japonicus in order to study its expression and characterize the structure of its precursor. A cDNA fragment was isolated using RT-PCR with two degenerate oligonucleotide primers that were designed based on the peptide sequence of Pej-SGP-IV, and this fragment was used as a probe to screen an eyestalk cDNA library. In a positive cDNA clone (814 base pairs (bp)), an open reading frame of 315 bp was found; the conceptually translated protein consists of a putative signal peptide (28 residues) and Pej-SGP-IV (77 residues). In Northern blot analysis using a cDNA probe, specific hybridization to a transcript of 0.95 kb was seen in RNA extracted from the eyestalk but not from hepatopancreas, abdominal muscle, brain, thoracic ganglia or abdominal ganglia. The level of the Pej-SGP-IV mRNA in the eyestalk did not change significantly during the molt cycle.

Animals↗
PubMed1997

A rare case of the right-sided aortic arch that has the right subclavian artery as the last branch.

This report describes a rare case of the right-sided aortic arch with the right subclavian artery as the last branch, which was encountered in a Japanese male cadaver in the dissecting room at Kurume University School of Medicine in 1995. In this subject, the ascending aorta arose from the left ventricle and ascended obliquely, curving forward and to the right, and became the right-sided aortic arch. The aortic arch passed upwards, reaching a summit at the level of the third thoracic vertebral body, then curved dorsally. The left brachiocephalic, the right common carotid and the right subclavian arteries came off the aortic arch in that order. After the right subclavian artery, the aortic arch dilated and formed the aortic diverticulum behind the trachea and the esophagus. The right thoracic aorta, a continuation of the aortic arch, descended to the right of the vertebral column. This case is a type M anomaly according to the Adachi-Williams-Nakagawa's classification, and is the twelfth case with this type of vascular variation to be reported in Japan.

Aged↗
PubMed1997

Cloning and sequence analysis of a cDNA encoding a crustacean hyperglycemic hormone from the Kuruma prawn Penaeus japonicus.

The crustacean hyperglycemic hormones (CHHs) are released from the X-organ sinus gland complex and regulate the glucose level in the hemolymph. In the present study, we have isolated a complementary DNA that encodes a CHH (Pej-SGP-III) of the Kuruma prawn Penaeus japonicus to study its expression and the structure of its precursor. In a cDNA clone of 774 base pairs (bp), an open reading frame of 345 bp was found. The conceptually translated protein consists of a signal peptide (24 residues), a CHH-precursor-related peptide (CPRP, 17 residues), and Pej-SGP-III (72 residues). This CPRP in P.japonicus was homologous to, but significantly shorter than, those in other crustacean species. In a Northern blot analysis, the cDNA specifically hybridized to a seemingly single mRNA species (approximately 0.8 kb) in the eyestalk. This mRNA was not detected in the hepatopancreas or abdominal muscle.

Amino Acid Sequence↗
PubMed1997

[Plasma cell leukemia associated with monocytosis].

A 51-year-old man was admitted to our hospital in December 1993, because of fatigue. Peripheral blood tests showed a WBC of 49,400/microliter with 36% plasma cells and 35% monocytes, Hb 14.5 g/dl, and Plt 137,000/microliter. Bone marrow aspirate revealed hypercellularity with 48.7% plasma cells and 22.4% monocytes. Plasma cells in blood were positive for CD38 and PCA-1. Serum calcium, IgA and M-CSF levels were elevated to 14.1 mg/dl, 2,337 mg/dl and 2.7 ng/ml, respectively. Immunoelectrophoresis of serum and urine revealed IgA lambda type M protein and lambda type Bence Jones protein, respectively. Rearrangements of immunoglobulin heavy chain and light chain were demonstrated by Southern blotting analysis. Plasma cell leukemia (IgA lambda type) was diagnosed. He was treated with combination chemotherapy and IFN-alpha and achieved complete remission. However, he suffered a meningeal relapse in February 1995, and died in April 1996. It seems likely that the enhanced production of M-CSF by myeloma cells and/ or activated B cells stimulated monocyte production.

Humans↗
PubMed1996

Cytophysiology of gonadotropin-releasing-hormone neurons in chum salmon (Oncorhynchus keta) forebrain before and after upstream migration.

Cytophysiology of gonadotropin-releasing-hormone neurons in chum salmon (Oncorhynchus keta) was examined before and after upstream migration by an immunocytochemical technique with a specific antiserum to salmon gonadotropin-releasing hormone and an in situ hybridization technique with an oligonucleotide encoding salmon gonadotropin-releasing hormone precursor (pro-salmon gonadotropin- releasing hormone). In the forebrain (olfactory nerve, olfactory bulb, telencephalon, and preoptic area), salmon gonadotropin-releasing hormone-immunoreactive neurons and neurons showing signals for pro-salmon gonadotropin-releasing hormone mRNA were compared between fish from the coastal sea and those from the spawning ground. Neurons in the dorsal region of the olfactory nerve and in the ventral region of the transitional area between olfactory nerve and olfactory bulb showed strong salmon gonadotropin-releasing-hormone immunoreactivity and strong hybridization signals in fish from the coastal sea, but these activities and signals were not observed or were decreased in number in fish from the spawning ground. The neurons in the olfactory bulb, telencephalon, and preoptic area consistently revealed salmon gonadotropin-releasing-hormone immunoreactivity and hybridization signals, and the hybridization signals of salmon gonadotropin-releasing hormone in the telencephalon and the preoptic area were stronger in fish from the spawning ground than in those from the coastal sea. These findings suggest that salmon gonadotropin-releasing-hormone neurons in the olfactory nerve and the transitional area between olfactory nerve and olfactory bulb have different patterns of hormone production than those in the telencephalon and the preoptic area.

Animals↗