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Biomedical subjects

Koji Inoue

Publications and source records attributed to Koji Inoue.

At least 19 recordsLinked to original sources
PubMed2006

In vitro effects of homologous natriuretic peptides on growth hormone and prolactin release in the tilapia, Oreochromis mossambicus.

C-type natriuretic peptide (CNP) cDNA was cloned from the tilapia brain and its inferred mature sequence was chemically synthesized together with previously cloned tilapia A-type and B-type natriuretic peptides (ANP and BNP). The cloned CNP belongs to the CNP-1 type of teleosts. Reverse-transcription polymerase chain reaction showed that the ANP and BNP genes were hardly expressed in the tilapia brain and pituitary, whereas the CNP gene was expressed strongly in the brain and slightly in the pituitary. Effects of homologous natriuretic peptides (100 nM each) on growth hormone (GH) and prolactin (PRL) release were examined using dispersed tilapia pituitary cells. Tilapia ANP and BNP stimulated GH and PRL release during 4-8, and 8-24 h of incubation. BNP appeared to be more potent than ANP, also stimulating GH and PRL release during 0-4 h of incubation. CNP stimulated GH release only during 4-8 h of incubation; CNP was without effect on PRL release. All three NPs stimulated GH and PRL mRNA expression in dispersed pituitary cells following 24 h of incubation. ANP and BNP significantly elevated intracellular cGMP accumulation in dispersed pituitary cells after 15 min of exposure, whereas no effect of CNP was observed. These results indicate a long-lasting stimulation of GH and PRL release by ANP and BNP that is mediated, at least in part, by the guanylyl cyclase-linked NP receptor.

Amino Acid Sequence↗
PubMed2006

Evolutionary history of the calcitonin gene-related peptide family in vertebrates revealed by comparative genomic analyses.

The calcitonin gene-related peptide (CGRP) family is composed of CGRP, amylin and adrenomedullin (AM) in mammals. In teleost fish, AM forms an independent subfamily of five members (AM1-5), which inspired us to trace the evolutionary history of the CGRP family throughout vertebrates by comparative genomic approach. Linkage mapping and synteny analyses of the CGRP family genes in medaka, Oryzias latipes, revealed that AM1/CGRP, AM2/amylin, and AM5 genes were located on respective proto-chromosomes before the divergence of teleost lineage. In teleost fish, additional whole genome duplication generated AM1/4, CGRP1/2, AM2/3, but one of the duplicated amylin and AM5 genes was silenced. In mammals, the amylin or AM2 gene was translocated to different chromosomes, while the CGRP gene was multiplied in tandem to generate CGRP-alpha,beta, and recently identified calcitonin receptor-stimulating peptide genes. Based on these data, we identified a novel AM5 gene in several mammalian species as we previously did for AM2.

Amino Acid Sequence↗
PubMed2006

Contribution of comparative fish studies to general endocrinology: structure and function of some osmoregulatory hormones.

Fish endocrinologists are commonly motivated to pursue their research driven by their own interests in these aquatic animals. However, the data obtained in fish studies not only satisfy their own interests but often contribute more generally to the studies of other vertebrates, including mammals. The life of fishes is characterized by the aquatic habitat, which demands many physiological adjustments distinct from the terrestrial life. Among them, body fluid regulation is of particular importance as the body fluids are exposed to media of varying salinities only across the thin respiratory epithelia of the gills. Endocrine systems play pivotal roles in the homeostatic control of body fluid balance. Judging from the habitat-dependent control mechanisms, some osmoregulatory hormones of fish should have undergone functional and molecular evolution during the ecological transition to the terrestrial life. In fact, water-regulating hormones such as vasopressin are essential for survival on the land, whereas ion-regulating hormones such as natriuretic peptides, guanylins and adrenomedullins are diversified and exhibit more critical functions in aquatic species. In this short review, we introduce some examples illustrating how comparative fish studies contribute to general endocrinology by taking advantage of such differences between fishes and tetrapods. In a functional context, fish studies often afford a deeper understanding of the essential actions of a hormone across vertebrate taxa. Using the natriuretic peptide family as an example, we suggest that more functional studies on fishes will bring similar rewards of understanding. At the molecular level, recent establishment of genome databases in fishes and mammals brings clues to the evolutionary history of hormone molecules via a comparative genomic approach. Because of the functional and molecular diversification of ion-regulating hormones in fishes, this approach sometimes leads to the discovery of new hormones in tetrapods as exemplified by adrenomedullin 2.

Adrenomedullin↗
PubMed2006

The significance of 123I-BMIPP delayed scintigraphic imaging in cardiac patients.

BACKGROUND: Earlier studies have not fully investigated the significance of radionuclide planar imaging in cardiac patients using the fatty acid analogue 123I-beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP). OBJECTIVES: This study was to clarify the effectiveness of 123I-BMIPP in assessing the heart-to-mediastinum ratio (H/M) and myocardial washout rate (WR) in patients with heart disease. METHODS: Myocardial 123I-BMIPP imaging was performed in 33 patients (20 with chronic heart failure [CHF] and 13 with stable angina pectoris [AP]) and 11 control subjects. Myocardial 123I-BMIPP planner images were obtained 30 min (early image) and 4 h (delayed image) after tracer injection. The left ventricular ejection fraction (LVEF) was measured by quantitative gated single photon emission computed tomography. The concentration of plasma brain natriuretic peptide (BNP) was measured before the scintigraphic study. RESULTS: (1) Delayed H/M was much lower in CHF than in AP (1.93 +/- 0.37 vs. 2.21 +/- 0.38, p < 0.05) and controls (vs. 2.47 +/- 0.38, p < 0.001). (2) The WR in CHF and AP were higher than the WR in controls (39.8 +/- 12.7% and 38.7 +/- 11.1 vs. 27.9 +/- 10.2%, p < 0.01 and p < 0.05, respectively). (3) In all subjects, LVEF was correlated with delayed H/M (r = 0.39, p < 0.01). And, the BNP was correlated with both the WR (r = 0.36, p < 0.05) and delayed H/M (r = - 0.29, p = 0.05). CONCLUSION: These data strongly suggest that the delayed H/M and myocardial WR of 123I-BMIPP enhances the assessment of the myocardial fatty acid metabolism disorders in patients with heart disease in both masked and unmasked conditions.

Aged↗
PubMed2006

Identification of two functional guanylin receptors in eel: multiple hormone-receptor system for osmoregulation in fish intestine and kidney.

Guanylyl cyclase C (GC-C) is a single transmembrane receptor for a family of intestinal hormones, guanylins. In the eel, we previously identified three guanylins, whose gene expression was enhanced in the intestine after transfer from fresh water to seawater. However, only limited information is available about the structure and function of their receptor(s). In the present study, we cloned full-length cDNAs encoding two isoforms of GC-C, named GC-C1 and GC-C2, from eel intestine. The predicted GC-C proteins consisted of extracellular ligand-binding domain, membrane-spanning domain, kinase-like domain and cyclase catalytic domain, in which GC-C-specific sequences were largely conserved. Phylogenetic analyses showed that the cloned membrane GCs are grouped with the GC-C of other vertebrates but not with GC-A and GC-B. However, eel GC-Cs appear to have undergone unique structural evolution compared with other GC-Cs. The three eel guanylins (guanylin, uroguanylin and renoguanylin), but not eel atrial natriuretic peptide, stimulated cGMP production dose-dependently in COS cells expressing either of the cloned cDNAs, providing functional support for assignment as eel guanylin receptors. The potency order for cGMP production was uroguanylin > guanylin > or = renoguanylin for GC-C1; guanylin > or = renoguanylin > uroguanylin for GC-C2. The distinctive ligand selectivity was consistent with the low homology (53%) of the extracellular domain of the two GC-Cs compared with that observed for other domains (74-90%). Both GC-C genes were expressed in the alimentary tract (esophagus, stomach and intestine) and kidney, and their expression was higher in the intestine of seawater-adapted eels than that of freshwater eels just as observed with the guanylin genes. However, the expression of the receptor genes was unchanged for 24h after transfer of eels from fresh water to seawater or vice versa, showing slower response of the receptors to salinity changes than their ligands. Collectively, the multiple guanylin-GC-C system may be involved as a paracrine factor in seawater adaptation at the intestine and kidney of the eel.

Amino Acid Sequence↗
PubMed2006

Adult onset of declining spermatogenesis in a man with nonmosaic Klinefelter's syndrome.

OBJECTIVE: To examine an unusual case of Klinefelter's syndrome. DESIGN: Case report. SETTING: An infertility clinic at a private hospital. PATIENT(S): A patient with nonmosaic Klinefelter's syndrome who had had a child with his ex-wife without artificial reproductive technologies. INTERVENTION(S): Karyotyping with peripheral blood lymphocytes, microdissection testicular sperm extraction, and intracytoplasmic sperm injection (ICSI). MAIN OUTCOME MEASURE(S): Sperm count and testicular histopathology. RESULT(S): Semen analysis revealed severe oligoasthenozoospermia. Intracytoplasmic sperm injection using ejaculated spermatozoa was performed, and successful pregnancy and delivery were achieved. Two years later, multiple semen analyses revealed azoospermia. Microdissection testicular sperm extraction was performed, and motile sperm were successfully retrieved. Unfortunately, the first cycle of ICSI using testicular sperm failed. Testicular histopathology was compatible with decreased spermatogenesis. CONCLUSION(S): This is a case of a man with nonmosaic Klinefelter's syndrome who exhibited progressive decline of spermatogenesis. This case suggests the merit of early sperm retrieval and cryopreservation for future management of infertility in Klinefelter's syndrome.

Adult↗
PubMed2006

Gender difference in the level of high-density lipoprotein cholesterol in elderly Japanese patients with coronary artery disease.

OBJECTIVE: High-density lipoprotein cholesterol (HDLC) levels are known to be reduced in the metabolic syndrome, but the HDLC profile of elderly patients with coronary artery disease (CAD) has not been well characterized. This study investigated the gender difference of HDLC levels in elderly Japanese patients with CAD. METHODS: Serum lipid data were analyzed retrospectively to assess sex-related differences of the lipid profile, and to evaluate the effects of pharmacotherapy or physical exercise on hyperlipidemia. PATIENTS: A total of 163 elderly (> or = 65 years) outpatients with CAD (128 men aged 70.6+/-5.2 years and 35 women aged 74.1+/-6.0 years [mean+/-SD]) were investigated. RESULTS: The mean total cholesterol (TC), low-density lipoprotein cholesterol (LDLC), and triglyceride (TG) levels were similar in men and women, while the mean HDLC level was significantly higher in women than men (58.3+/-18.1 vs. 50.3+/-13.5 mg/dL; p=0.0064). The HDLC level was not significantly influenced by oral lipid-lowering therapy or regular exercise in either sex. However, women without lipid-lowering therapy had significantly higher HDLC levels than men with (p=0.0312) or without (p=0.0338) lipid-lowering therapy, while women performing regular exercise had significantly higher HDLC levels than men with (p=0.0047) or without (p<0.001) regular exercise. CONCLUSION: Elderly women with CAD have higher HDLC levels relative to their postmenopausal state than those of men with CAD. Low HDLC levels, unlike in men, may not be a major risk factor for CAD in elderly women.

Aged↗
PubMed2006

Testosterone-induced priapism in Klinefelter syndrome.

We present the case of a patient with Klinefelter syndrome and priapism after testosterone administration. The patient underwent testicular sperm extraction for interventional fertilization, but no sperm were found. Because he had given up trying to father a child and his testosterone level had been low, testosterone replacement therapy was started with testosterone enanthate. After the third injection, he presented with low-flow priapism. Conservative management was successful, and no recurrence developed during the next 15 months. Testosterone replacement therapy carries some risk of priapism even for patients with Klinefelter syndrome.

Adult↗
PubMed2006

Multiple natriuretic peptides coexist in the most primitive extant ray-finned fish, bichir Polypterus endlicheri.

Natriuretic peptides (NPs) have diversified from a single NP in cyclostomes and elasmobranchs to multiple NPs in ray-finned fishes where ANP, BNP, VNP, and/or up to four CNPs (CNP-1, 2, 3, and/or 4) have been identified. To trace the evolutionary diversification of NPs in fishes, we analyzed the bichir (Polypterus endlicheri), believed to be the most primitive extant ray-finned fish, for the presence of any NPs by a PCR-based method using primers that amplify all NP cDNAs identified to date. We have cloned cDNAs encoding ANP, BNP, VNP from the heart and three CNPs (CNP-1, 3, and 4) from the brain. An extensive search for CNP-2 from the brain was not successful. The C-terminus of bichir ANP presented an amidation signal as in ray-finned fish ANP. The bichir BNP mRNA had AUUUA repeats in the 3'-untranslated region as observed in all BNP cDNAs of vertebrates. The bichir VNP had a long C-terminal 'tail' sequence extending from the intramolecular ring as does teleost VNP. The three bichir CNPs are structurally similar to each teleost counterpart and are grouped after molecular phylogenetic analyses. ANP was most abundantly expressed in the atrium, BNP in the ventricle, and VNP was expressed in both atrium and ventricle. The three CNPs are most abundantly expressed in the brain, and CNP-4 transcripts were found in small amounts in the ventricle and kidney. Taken together, it is clear that all major NPs exist prior to the whole genome duplication that occurred in the teleost lineage. Furthermore, this is the first observation that CNP-3, ANP, BNP, and VNP, whose genes are colocalized in the same chromosome, coexist in a single fish species including teleosts, thereby confirming that CNP-3 is not an ortholog of VNP, and that ANP, BNP, and VNP genes were generated by tandem duplication from the CNP-3 gene.

Amino Acid Sequence↗
PubMed2006

Anti-fibrotic effects of theophylline on lung fibroblasts.

Theophylline has been used in the management of bronchial asthma and chronic obstructive pulmonary disease for over 50 years. It has not only a bronchodilating effect, but also an anti-inflammatory one conducive to the inhibition of airway remodeling, including subepithelial fibrosis. To date however, whether theophylline has a direct inhibitory effect on airway fibrosis has not been established. To clarify this question, we examined whether theophylline affected the function of lung fibroblasts. Theophylline suppressed TGF-beta-induced type I collagen (COL1) mRNA expression in lung fibroblasts and also inhibited fibroblast proliferation stimulated by FBS and TGF-beta-induced alpha-SMA protein. A cAMP analog also inhibited TGF-beta-induced COL1 mRNA expression in lung fibroblasts. A PKA inhibitor reduced the inhibitory effect of theophylline on TGF-beta-induced COL1 mRNA expression. These results indicate that theophylline exerts anti-fibrotic effects, at least partly, through the cAMP-PKA pathway.

Cell Line↗
PubMed2006

The gefitinib-sensitizing mutant epidermal growth factor receptor enables transformation of a mouse fibroblast cell line.

A specific inhibitor of the Epidermal Growth Factor Receptor (EGFR), Gefitinib, displays significant antitumor effects against non-small cell lung cancers (NSCLC) that express EGFR with mutations in their tyrosine kinase domain. Although previous reports have already demonstrated that oncogenic transformation can be induced by some mutant EGFR forms, the precise differences between mutant and wild-type EGFR in terms of mechanisms of transformation have not been fully elucidated. We show here that a murine fibroblast cell line, NR6 becomes transformed by an expression level of the mutant EGFR form lacking E746-A750 that is far less than that needed with transfected wild-type EGFR. However, the mutant EGFR was unable to transform NR6 in a ligand-independent manner, as was seen with the wild-type EGFR. The consequent biological features after transformation, including DNA synthesis or cell cycle progression and biochemical characteristics such as MAPK activation mediated by the mutant EGFR are comparable and equivalent to those mediated by wild-type EGFR. These data suggest that the mutant EGFR possesses greater ligand-dependent transformation when compared with wild-type EGFR, although the exact mechanisms to account for this characteristic remain to be defined.

Animals↗
PubMed2006

Automatic switching and guidance system to facilitate unassisted uroflowmetry using commercial electronic devices.

To enable male patients to undergo uroflowmetry in a private condition without medical supervision, we devised an automatic switching and patient guidance system for the spinning disk uroflowmeter Urodyn 1000, using two commercial electronic devices (an infrared motion sensor tap and a memorizable vacuum fluorescent display). Instead of running the uroflowmeter continuously, which shortens the life of the spinning disk due to mechanical wear, an infrared motion sensor turns on the devices each time a patient enters the room. The patient urinates according to the timely instructions on the visible display and voided urine directly flows into a urinal. The devices are automatically turned off 5 min after the patient leaves the room. With the use of our system, men already acquainted with uroflowmetry could perform self-administered uroflowmetry any time in private. The system was considered useful for improving the quality of patient service.

Ambulatory Care↗
PubMed2006

Application of siphon principle to fluid drainage in transurethral surgery.

Transurethral resection is usually performed using an all-in-one drape with a fluid collection pouch, drainage port and hose. Gravity drainage of irrigation fluid through the hose is often hampered, resulting in fluid retention in the pouch. We applied a siphon principle to facilitate fluid drainage by making a U-shaped bend near the distal end of the hose, using an adhesive tape, and hooking the distal end of inverted U shape on the edge of bucket placed on the floor. When the hose is filled with irrigation fluid up to the crest of the siphon, fluid flow driven by atmospheric pressure continues until the pouch is evacuated. Repriming and restarting occur automatically throughout the operation. This simple device has virtually eliminated fluid retention in the pouch and proved to be especially useful in transurethral prostatectomy, which requires a large amount of irrigation fluid.

Drainage↗
PubMed2006

Antibiotic prophylaxis in radical prostatectomy: 1-day versus 4-day treatments.

OBJECTIVE: The standard protocol of antibiotic prophylaxis in radical prostatectomy remains to be established. We retrospectively compared the occurrence of perioperative infections following radical prostatectomy between two different protocols of antibiotic prophylaxis. METHODS: This study included 106 cases of radical retropubic prostatectomy managed on the clinical pathways. Two different protocols of antibiotic prophylaxis were used in otherwise identical pathways. Between January and December 2004, 50 patients received a second generation cephem, cefotiam, for 4 days, beginning 30 min before surgery (4-day group), whilst between December 2004 and July 2005, only two doses of cefotiam were given on the day of operation in 56 patients (1-day group). The incidence of surgical site infection (SSI) and remote infection (RI) was retrospectively investigated. RESULTS: Superficial incisional SSI occurred in one (1.8%) patient in the 1-day group, whereas no patient in the 4-day group developed SSI. No RI was observed in either the 1-day or 4-day group. Intravenous antibiotics were administered besides the pathway in a patient in the 1-day group because unexplained fever more than 38 degrees C continued postoperative day (POD) 2 through POD 4 without signs of SSI or RI. Excluding this case, postoperative more than 38 degrees C was rare and transient after POD 2. CONCLUSION: The incidence of SSI and RI was low and not significantly different between the 1-day and 4-day groups. Therefore, the 1-day protocol of prophylactic antibiotic treatment seems adequate for preventing perioperative infections in radical prostatectomy.

Aged↗
PubMed2006

Functional capacity, skeletal muscle strength, and skeletal muscle volume in patients with myocardial infarction.

Previous studies have reported that skeletal muscle strength is closely related to exercise capacity in patients with myocardial infarction (MI). However, none of the previous studies have fully investigated the correlation between exercise capacity and the skeletal muscle volume (MV). Seventy patients with MI underwent symptom-limited cardiopulmonary exercise testing using a treadmill. The MV was evaluated by electrical impedance analysis and the maximal knee extension strength (Peak torque: PT) was measured by a Biodex. The subjects were divided into 2 groups according to the MV (group L, MV < 22 kg; group H, MV > or = 22 kg). The PT was positively and significantly correlated with the peak V(.)O(2) in both the L and H groups (r = 0.70 versus r = 0.71). The MV of the lower limbs was positively correlated with the peak V(.)O(2) in the L group (r = 0.57), but not in the H group. The lower limb MV was positively and significantly correlated with PT in the L group (r = 0.48), but not in the H group. The exercise capacity of patients with MI is thought to depend on both the strength and volume of the skeletal muscle. In MI patients with high muscle volume, exercise capacity was determined by skeletal muscle strength alone.

Electric Impedance↗
PubMed2005

Structural and functional evolution of three cardiac natriuretic peptides.

Natriuretic peptides (NPs) are a group of hormones playing important roles in cardiovascular and osmoregulatory systems in vertebrates. Among the NP subtypes, atrial NP (ANP), B-type NP (BNP), and ventricular NP (VNP) are circulating hormones expressed exclusively in the heart (cardiac NPs). The constitution of cardiac NPs is variable among species of vertebrates. In order to understand the evolutionary and functional significance of such variation, we performed a systematic survey of cardiac NP cDNAs in nine taxonomically diverse teleosts inhabiting environments of varying salinity. The discovery of the coexistence of the ANP, BNP, and VNP genes in the eel and rainbow trout suggested that the ancestral teleost had all three cardiac NPs. As the VNP cDNA was undetectable in ayu and six species of Neoteleostei, it is possible that VNP was lost before the divergence of Osmeroidei. The ANP gene was also undetectable in the medaka. Thus, only the BNP gene is universal in species examined in the present study. Synthetic medaka BNP preferentially activated two medaka GC-A-type receptors, suggesting that the three cardiac NPs share the same receptor. However, the regulation of BNP expression may be the most strict because ATTTA repeats in the 3'-untranslated region and the dibasic motif in the ring are conserved among teleosts and tetrapods. Linkage analyses in the rainbow trout located ANP, BNP, and VNP genes on the same chromosome, which suggested the generation of the VNP gene by tandem duplication as observed with ANP and BNP genes. If the duplication occurred before the divergence of tetrapods and teleosts, VNP may exist in the tetrapod lineage.

Amino Acid Sequence↗
PubMed2005

Cigarette smoke extract induces endothelial cell injury via JNK pathway.

Cigarette smoking is the most crucial factor responsible for chronic obstructive pulmonary disease (COPD). The precise mechanisms of the development of the disease have, however, not been fully understood. Recently, impairment of pulmonary endothelial cells has been increasingly recognized as a critical pathophysiological process in COPD. To verify this hypothesis, we examined how cigarette smoke extract (CSE) damages human umbilical vein endothelial cells (HUVECs). CSE activated c-Jun N-terminal kinase (JNK), and treatment of HUVECs with SP600125, a specific inhibitor of the JNK pathway, significantly suppressed endothelial cell damage by CSE. In contrast, inhibition of the extracellular-regulated kinase or the p38 pathway did not affect the cytotoxicity of CSE. Furthermore, anti-oxidants superoxide dismutase and catalase reduced CSE-induced JNK phosphorylation and endothelial cell injury. These results indicate that CSE damages vascular endothelial cells through the JNK pathway activated, at least partially, by oxidative stress.

Animals↗