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Tsukahara Y, Nose-Ogura S, Kinoshita S, Nakamura H, Koshimizu T, Gleason CN, Mason RA, Harada M, Hiraike O, Osuga Y. Differences in screening and treating relative energy deficiency in sport between the United States of America and Japan. J Sports Med Phys Fitness 2024; 64:175-182. [PMID: 38015478 DOI: 10.23736/s0022-4707.23.15302-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
BACKGROUND The diagnosis and treatment of relative energy deficiency in sport (RED-S) are challenging owing to variations in symptoms and the absence of specific guidelines. This study aimed to investigate differences in the diagnosis and follow-up of RED-S, its consequences, and related factors among sports medicine physicians with different backgrounds in Japan and the USA and examine the differences between the two countries. METHODS An anonymous survey regarding the diagnosis and treatment processes of RED-S was distributed to sports medicine physicians via email. Respondents included 58 sports medicine physicians from the USA and 241 from Japan. RESULTS The findings showed that 77.6% of the US physicians screened athletes for RED-S, whereas 17.5% of their Japanese counterparts did so. Moreover, 98.3% and 36.7% of the US and Japanese physicians, respectively, answered that they screened athletes for eating disorders upon suspicion of low energy availability. Logistic regression analysis revealed that the number of US sports medicine physicians who screened athletes for the female athlete triad (Triad) and RED-S (odds ratio [OR] = 12.78, P<0.001) and adhered to specific criteria for athlete suspension and return-to-play (OR=33.67, P<0.01) was higher than that of their Japanese counterparts. CONCLUSIONS The prevalence of RED-S-related screening and treatment differed between US and Japanese sports medicine physicians. Educating sports medicine physicians about the diagnosis and treatment of athletes with possible signs of RED-S is important in treating female athletes and further investigations are required to identify why the physicians screened/not screened the athletes.
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Affiliation(s)
- Yuka Tsukahara
- Department of Sports Medicine, Tokyo Women's College of Physical Education, Tokyo, Japan
| | - Sayaka Nose-Ogura
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Sakiko Kinoshita
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Hiroe Nakamura
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Takako Koshimizu
- Department of Food Science, Otsuma Women's University, Tokyo, Japan
| | - Courtney N Gleason
- School of Medicine, Division of Sports Medicine, Department of Orthopedics, Emory University, Atlanta, GA, USA
| | - Rudolph A Mason
- School of Medicine, Division of Sports Medicine, Department of Orthopedics, Emory University, Atlanta, GA, USA
| | - Miyuki Harada
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Osamu Hiraike
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Yutaka Osuga
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
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2
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Chiba Y, Nose-Ogura S, Sekiguchi K, Eda K, Nakamura H, Koshimizu T, Yamamoto H, Yamaguchi T, Harada M, Wada-Hiraike O, Osuga Y. Development of University of Tokyo's eating disorders inventory in female athletes. J Obstet Gynaecol Res 2023. [PMID: 37088869 DOI: 10.1111/jog.15637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 03/07/2023] [Indexed: 04/25/2023]
Abstract
AIMS This study aimed to develop a scale to screen for eating disorders in female athletes. METHODS Preliminary survey: A total of 275 female athletes (mean age: 19.4 ± 1.0 years) and 7 female athletes diagnosed with eating disorders (mean age: 20.1 ± 2.5 years) were administered screening items prepared based on an existing scale, followed by exploratory factor analysis. Main survey: Six items, relating to three factors, were extracted, and 201 female athletes (mean age: 22.3 ± 4.8 years) and 6 female athletes diagnosed with current or a history of eating disorders (mean age: 18.8 ± 2.9 years) were queried. The diagnostic validity of the scale was then evaluated. RESULTS Preliminary survey: Questions (α = 0.71) were extracted from six items, relating to three factors, and collectively termed the University of Tokyo's eating disorders inventory in female athletes (TEDIFA). To determine the scale cut-off score, ROC analysis was performed with the total score, and the cut-off and gray zone scores were set at 13 and 11, respectively. Main survey: At the cut-off score of 13, AUC, sensitivity, and specificity were 0.83 (p < 0.05), 75%, and 90%, respectively. CONCLUSIONS The scale that was developed, TEDIFA, consisted of six items. The cut-off scores were set at 11 for the gray zone (sensitivity: 75%; specificity: 56%; accurate diagnosis rate: 60%), and 13 for positivity (sensitivity: 75%; specificity: 90%; accurate diagnosis rate: 87%), demonstrating the reliability and validity of the scale.
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Affiliation(s)
- Yoko Chiba
- Department of Psychological and Behavioral Science Faculty of Liberal Arts, Miyagi Gakuin Women's University, Sendai, Japan
| | - Sayaka Nose-Ogura
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Kuniko Sekiguchi
- Sports Clinic, Sports Medical Center, Japan Institute of Sports Sciences, Japan High Performance Sport Center, Tokyo, Japan
- Meguro Ekimae Mental Clinic, Tokyo, Japan
| | - Kaori Eda
- Conditioning Section, Sports Medical Center, Japan Institute of Sports Sciences, Japan High Performance Sport Center, Tokyo, Japan
| | - Hiroe Nakamura
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Takako Koshimizu
- Department of Food Science Faculty of Home Economics Major in Food Science, Otsuma Women's University, Tokyo, Japan
| | - Hiroaki Yamamoto
- Department of Psychiatry, Kitasato University Medical Center, Kitamoto, Japan
| | - Tatsuya Yamaguchi
- Department of Neuropsychiatry, Keio University, Tokyo, Japan
- Institute for Integrated Sports Medicine, School of Medicine, Keio University, Tokyo, Japan
- Sports Medical Research Center, Keio University, Yokohama, Japan
- Sports Medicine Laboratory, School of Medicine, Graduate School of Health and Sports Science, Juntendo University, Tokyo, Japan
| | - Miyuki Harada
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Osamu Wada-Hiraike
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
| | - Yutaka Osuga
- Department of Obstetrics and Gynecology, University of Tokyo Hospital, Tokyo, Japan
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3
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Koshimizu T, Matsushima Y, Yokota Y, Yanagisawa K, Nagai S, Okamura K, Komatsu Y, Kawahara T. Basal metabolic rate and body composition of elite Japanese male athletes. J Med Invest 2013; 59:253-60. [PMID: 23037196 DOI: 10.2152/jmi.59.253] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The estimated energy requirement is important for adequate nutritional management in athletes. The energy requirement can be estimated from the basal metabolic rate (BMR). However, there is little data regarding the BMR of Japanese athletes. This study measured the BMR and body composition of 81 elite Japanese male athletes in different sports categories: endurance (E), strength, power and sprint (S) and ball game (B). The factors influencing the BMR were also investigated. The BMR and body composition were measured by indirect calorimetry and an air-displacement plentysmograph device (the BOD POD), respectively. The BMR per lean body mass (LBM) differed significantly among the three groups. The BMR was significantly correlated with the body weight (BW) and LBM in all groups. A multiple-regression analysis showed that the LBM was the most powerful predictor in the E and S groups, whereas the BW was the most powerful predictor in the B group. The BW appears to become an important predictor as the BW of athletes increases. Additionally, height was the second explanatory variable in the S and B groups, thus suggesting that height needs to be considered for the BMR in these groups. Therefore, the BMR in elite athletes needs to be estimated according to their body composition.
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Affiliation(s)
- Takako Koshimizu
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
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4
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Masuki S, Koshimizu T, Qian J, Higuchi K, Tsujimoto G, Nose H. Voluntary locomotion linked with cerebral activation is reduced in vasopressin V1a receptor knockout mice. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1054.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - T. Koshimizu
- Genomic Drug Discov. Sci., Grad. Sch. Pharm. Sci.Kyoto Univ.KyotoJapan
| | - J. Qian
- Aging Biol.Shinshu Univ. Grad. Sch. Med.MatsumotoJapan
| | - K. Higuchi
- Aging Biol.Shinshu Univ. Grad. Sch. Med.MatsumotoJapan
| | - G. Tsujimoto
- Genomic Drug Discov. Sci., Grad. Sch. Pharm. Sci.Kyoto Univ.KyotoJapan
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5
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Kondo E, Koshimizu T, Tai S, Okada S, Okamura K. Effects of a high protein diet and the timing of protein consumption after exercise on glucocorticoid‐induced muscle atrophy in rats. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.740.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Emi Kondo
- Osaka Univ. of Health and Sport Sci.OsakaJapan
| | | | - Shinji Tai
- Osaka Univ. of Health and Sport Sci.OsakaJapan
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6
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Michiko D, Yokota Y, Koshimizu T, Matsushima Y, Ebi K, Tatsuta W, Kamei A, Uemura K, Maita S, Yanagisawa K, Kamihigashi E, Beinert T, Shirai K, Enoki T, Takahashi H, Akama T, Komatsu Y, Kawahara T. Supplement Usage Of Elite Japanese Athletes. Med Sci Sports Exerc 2008. [DOI: 10.1249/01.mss.0000322703.02960.dc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Masuki S, Koshimizu T, Zhang B, Higuchi K, Tsujimoto G, Nose H. Enhancement of cardiac baroreflex sensitivity in acute hypovolemia is abolished in vasopressin V1a receptor knockout mice. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.737.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S. Masuki
- Department of Sports Medical Sciences
| | - T. Koshimizu
- Department of Genomic Drug Discovery ScienceGraduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - B. Zhang
- Department of Aging BiologyShinshu University Graduate School of MedicineMatsumotoJapan
| | - K. Higuchi
- Department of Aging BiologyShinshu University Graduate School of MedicineMatsumotoJapan
| | - G. Tsujimoto
- Department of Genomic Drug Discovery ScienceGraduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - H. Nose
- Department of Sports Medical Sciences
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Abstract
In this article the role of the bootstrap is highlighted for nonlinear discriminant analysis using a feedforward neural network model. Statistical techniques are formulated in terms of the principle of the likelihood of a neural-network model when the data consist of ungrouped binary responses and a set of predictor variables. We illustrate that the information criterion based on the bootstrap method is shown to be favorable when selecting the optimum number of hidden units for a neural-network model. In order to summarize the measure of goodness-of-fit, the deviance on fitting a neural-network model to binary response data can be bootstrapped. We also provide the bootstrap estimates of the biases of excess error in a prediction rule constructed by fitting to the training sample in the neural network model. We additionally propose bootstrap methods for the analysis of residuals in order to identify outliers and examine distributional assumptions in neural-network model fitting. These methods are illustrated through the analyzes of medical diagnostic data.
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Affiliation(s)
- M Tsujitani
- Department of Engineering Informatics, Faculty of Information Science and Arts, Osaka Electro-Communication University, Osaka 572-8530, Japan.
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9
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Ishizaki S, Koshimizu T, Yanagisawa K, Akiyama Y, Mekada Y, Shiozawa N, Takahashi N, Yamakawa J, Kawano Y. Effects of a fixed dietary intake on changes in red blood cell delta-aminolevulinate dehydratase activity and hemolysis. Int J Sport Nutr Exerc Metab 2007; 16:597-610. [PMID: 17342881 DOI: 10.1123/ijsnem.16.6.597] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study was to assess the effect of a fixed dietary intake on biomarkers of red blood cell (RBC) biosynthesis and degradation. Over a two-year period, eight collegiate rhythmic gymnasts participated in this study. During the first year, they ate self-selected diets. During the second year, a fixed dietary intake involving consumption of common Japanese foods containing 15 mg iron and 1500 kcal energy was maintained for 4 wk at the beginning of the program. Fixed dietary intakes resulted in significantly increased intakes of protein, minerals and vitamins, and significantly decreased fat intake, but total energy and carbohydrate intakes were unchanged. Mean values of RBC, Hb, Ht, or TIBC were not affected by the intervention. A fixed dietary intervention appeared to enhance RBC turnover by increasing the capacity for erythrocyte biosynthesis and degradation, although the prevalence of iron-deficiency anemia remained unchanged.
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Affiliation(s)
- Sakuko Ishizaki
- Japan Women's College of Physical Education, Tokyo 157-8565, Japan
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10
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Muraishi O, Mitsu S, Suzuki K, Koshimizu T, Tokue A. A technique for resection of small bladder tumors using a flexible cystoscope on an outpatient basis: bladder tumor resection with newly designed hot cup forceps. J Urol 2001; 166:1817-9. [PMID: 11586231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
PURPOSE We describe a technique for resecting small papillary superficial bladder tumors using a new device and flexible cystoscope. MATERIALS AND METHODS In a 79-year-old man 3 small recurrent papillary bladder tumors were resected transurethrally on an outpatient basis. The procedure was performed using a flexible cystoscope and a newly designed type of cup forceps with the patient under topical anesthesia. No urethral catheter remained indwelling after surgery and the patient was discharged home the same day. RESULTS Bladder tumor resection using this technique was tolerable to the patient and postoperative bladder hemorrhage was not noted. Resected specimens were adequate for pathological tumor evaluation, which revealed grade 1 stage Ta superficial transitional cell carcinoma of the bladder. CONCLUSIONS This easy technique seems to be tolerated well by the patient. Resected specimens should be adequate for evaluating the pathological grade and depth of stage Ta or T1 superficial bladder cancer. This technique may be an alternative to standard transurethral resection for removing small recurrent bladder lesions in select patients who prefer outpatient management of bladder tumors.
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Affiliation(s)
- O Muraishi
- Department of Urology, Jichi Medical School, Tochigi, Japan
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11
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Abstract
Pituitary cells secrete ATP, which acts as an autocrine and/or paracrine extracellular messenger on two families of purinergic receptors: G-protein-coupled P2Y receptors (P2YRs) and ion-conducting P2X receptors (P2XRs). Lactotrophs and GH(3)-immortalized cells express the P2Y(2)R subtype. Several P2XR subtypes are expressed in pituitary cells. Gonadotrophs and somatotrophs express P2X(2a)R and P2X(2b)R, which occur as heteromeric channels. Lactotrophs and GH(3) cells express one or more ion-conducting subtypes from among P2X(3)R, P2X(4)R and P2X(7)R in homomeric form. Thyrotrophs and corticotrophs also express P2XRs, but their identification requires further study. Pituitary cells express purinergic P1 receptors, which are activated by adenosine. The A(1)R subtype of these receptors is expressed in melanotrophs and GH(3) cells. In this review, we briefly discuss the expression and coupling of A(1)R and P2Y(2)R, and focus on the expression and Ca(2+) signaling of P2XRs.
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Affiliation(s)
- S S Stojilkovic
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, 20892-4510, Bethesda MD, USA.
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12
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Stojilkovic SS, Tomic M, Van Goor F, Koshimizu T. Expression of purinergic P2X2 receptor-channels and their role in calcium signaling in pituitary cells. Biochem Cell Biol 2001; 78:393-404. [PMID: 10949088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Pituitary cells express purinergic receptor-channels (P2XR), the activation of which by ATP is associated with the facilitation of Ca2+ influx. Pharmacological, RT-PCR, and nucleotide sequence analyses confirm the presence of a wild type P2X2aR and a spliced isoform P2X2bR, which lacks a portion of carboxyl terminal amino acids. Wild type and spliced isoform receptors have a similar EC50 for ATP and time-course for activation, but the spliced isoform exhibits rapid and complete desensitization, whereas the wild type channel desensitizes slowly and incompletely. Deletion and insertion studies have revealed that a 6 residue sequence located in carboxyl tail (Arg371-Pro376) is required for sustained Ca2+ influx through wild type receptors. When co-expressed, the wild type and spliced channels form functional heteropolymeric channels. The patterns of Ca2+ signaling in the majority of pituitary cells expressing ATP-gated receptor-channels are highly comparable to those observed in cells co-transfected with P2X2aR and P2X2bR. ATP-induced [Ca2+]i response in pituitary cells is partially inhibited by nifedipine, a blocker of voltage-gated L-type Ca2+ channels, suggesting that P2X2R not only drive Ca2+ into the cell, but also activate voltage-gated Ca2+ entry. Our results indicate that ATP represents a paracrine and (or) autocrine factor in the regulation of Ca2+ signaling, and that its actions are mediated in part by heteropolymeric P2X2R.
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Affiliation(s)
- S S Stojilkovic
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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13
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Abstract
The role of nitric oxide (NO) in the stimulation of soluble guanylyl cyclase (sGC) is well established, but the mechanism by which the enzyme is inactivated during the prolonged NO stimulation has not been characterized. In this paper we studied the interactions between NO and intracellular Ca(2+) in the control of sGC in rat anterior pituitary cells. Experiments were done in cultured cells, which expressed neuronal and endothelial NO synthases, and in cells with elevated NO levels induced by the expression of inducible NO synthase and by the addition of several NO donors. Basal sGC-dependent cGMP production was stimulated by the increase in NO levels in a time-dependent manner. In contrast, depolarization of cells by high K(+) and Bay K 8644, an L-type Ca(2+) channel agonist, inhibited sGC activity. Depolarization-induced down-regulation of sGC activity was also observed in cells with inhibited cGMP-dependent phosphodiesterases but not in cells bathed in Ca(2+)-deficient medium. This inhibition was independent from the pattern of Ca(2+) signaling (oscillatory versus nonoscillatory) and NO levels, and was determined by averaged concentration of intracellular Ca(2+). These results indicate that inactivation of sGC by intracellular Ca(2+) serves as a negative feedback to break the stimulatory action of NO on enzyme activity in intact pituitary cells.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Signaling/drug effects
- Cells, Cultured
- Cyclic AMP/metabolism
- Cyclic GMP/metabolism
- Dose-Response Relationship, Drug
- Female
- Guanidines/pharmacology
- Guanylate Cyclase/metabolism
- Isoenzymes/metabolism
- Nitric Oxide/metabolism
- Nitric Oxide Donors/pharmacology
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase/metabolism
- Nitroprusside/pharmacology
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/enzymology
- Pituitary Gland, Anterior/metabolism
- Potassium/pharmacology
- Rats
- Rats, Sprague-Dawley
- Solubility
- Vinca Alkaloids/pharmacology
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Affiliation(s)
- S A Andric
- Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892-4510, USA
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14
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Abstract
The P2X purinergic receptor channels (P2XRs) differ among themselves with respect to the rates of desensitization during prolonged agonist stimulation. Here we studied the desensitization of recombinant channels by monitoring the changes in intracellular free Ca(2+) concentration in cells stimulated with ATP, the native and common agonist for all P2XRs. The focus in our investigations was on the relevance of the P2XR C terminus in controlling receptor desensitization. When expressed in GT1 cells, the P2XRs desensitized with rates characteristic to each receptor subtype: P2X(1)R = P2X(3)R > P2X(2b)R > P2X(4)R > P2X(2a)R > P2X(7)R. A slow desensitizing pattern of P2X(2a)R was mimicked partially by P2X(3)R and fully by P2X(4)R when the six-amino acid sequences of these channels located in the cytoplasmic C terminus were substituted with the corresponding arginine 371 to proline 376 sequence of P2X(2a)R. Changing the total net charge in the six amino acids of P2X(4)R to a more positive direction also slowed the receptor desensitization. On the other hand, substitution of arginine 371-proline 376 sequence of P2X(2a)R with the corresponding sequences of P2X(1)R, P2X(3)R, and P2X(4)R increased the rate of receptor desensitization. Furthermore, heterologous polymerization of wild-type P2X(2a)R and mutant P2X(3)R having the C-terminal six amino acids of P2X(2a)R at its analogous position resulted in a functional channel whose desensitization was significantly delayed. These results suggest that composition of the C-terminal six-amino acid sequence and its electrostatic force influence the rate of receptor desensitization.
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Affiliation(s)
- T Koshimizu
- Endocrinology Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA
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15
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Tomić M, Koshimizu T, Yuan D, Andric SA, Zivadinovic D, Stojilkovic SS. Characterization of a plasma membrane calcium oscillator in rat pituitary somatotrophs. J Biol Chem 1999; 274:35693-702. [PMID: 10585449 DOI: 10.1074/jbc.274.50.35693] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In excitable cells, oscillations in intracellular free calcium concentrations ([Ca(2+)](i)) can arise from action-potential-driven Ca(2+) influx, and such signals can have either a localized or global form, depending on the coupling of voltage-gated Ca(2+) influx to intracellular Ca(2+) release pathway. Here we show that rat pituitary somatotrophs generate spontaneous [Ca(2+)](i) oscillations, which rise from fluctuations in the influx of external Ca(2+) and propagate within the cytoplasm and nucleus. The addition of caffeine and ryanodine, modulators of ryanodine-receptor channels, and the depletion of intracellular Ca(2+) stores by thapsigargin and ionomycin did not affect the global nature of spontaneous [Ca(2+)](i) signals. Bay K 8644, an L-type Ca(2+) channel agonist, initiated [Ca(2+)](i) signaling in quiescent cells, increased the amplitude of [Ca(2+)](i) spikes in spontaneously active cells, and stimulated growth hormone secretion in perifused pituitary cells. Nifedipine, a blocker of L-type Ca(2+) channels, decreased the amplitude of spikes and basal growth hormone secretion, whereas Ni(2+), a blocker of T-type Ca(2+) channels, abolished spontaneous [Ca(2+)](i) oscillations. Spiking was also abolished by the removal of extracellular Na(+) and by the addition of 10 mM Ca(2+), Mg(2+), or Sr(2+), the blockers of cyclic nucleotide-gated channels. Reverse transcriptase-polymerase chain reaction and Southern blot analyses indicated the expression of mRNAs for these channels in mixed pituitary cells and purified somatotrophs. Growth hormone-releasing hormone, an agonist that stimulated cAMP and cGMP productions in a dose-dependent manner, initiated spiking in quiescent cells and increased the frequency of spiking in spontaneously active cells. These results indicate that in somatotrophs a cyclic nucleotide-controlled plasma membrane Ca(2+) oscillator is capable of generating global Ca(2+) signals spontaneously and in response to agonist stimulation. The Ca(2+)-signaling activity of this oscillator is dependent on voltage-gated Ca(2+) influx but not on Ca(2+) release from intracellular stores.
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Affiliation(s)
- M Tomić
- Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892-4510, USA
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16
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Affiliation(s)
- O Muraishi
- Department of Urology, Jichi Medical School, Tochigi, Japan
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17
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Katzur AC, Koshimizu T, Tomić M, Schultze-Mosgau A, Ortmann O, Stojilkovic SS. Expression and responsiveness of P2Y2 receptors in human endometrial cancer cell lines. J Clin Endocrinol Metab 1999; 84:4085-91. [PMID: 10566654 DOI: 10.1210/jcem.84.11.6119] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In single endometrial carcinoma HEC-1A and Ishikawa cells, ATP induced a rapid and extracellular Ca2+-independent rise in cytosolic Ca2+ concentration ([Ca2+]i) in a dose-dependent manner, with an ED50 of about 10 microM. The spike phase was followed by a sustained plateau phase that was dependent on Ca2+ influx through voltage-insensitive Ca2+ channels, whose gating was controlled by a capacitative Ca2+ entry mechanism. ADP was less potent in raising the cystolic Ca2+ concentration, and AMP and adenosine were ineffective. The order of agonist potency for this receptor was ATP = UTP > ATP-gamma-S >> ADP. Several other agonists, including beta,gamma-methylene-ATP, 2-MeS-ATP, and BzATP were ineffective. This ligand-selective profile indicates the expression of the P2Y2R subtype in endometrial cells. Accordingly, reverse transcription-PCR using P2Y2 primers amplified the expected transcript from both cell lines. The coupling of these receptors to phospholipase C was confirmed by the ability of ATP to increase inositol 1,4,5-trisphosphate and diacylglycerol productions. These receptors are also coupled to the phospholipase D-1 pathway, leading to accumulation of phosphatidic acid. Activation of P2Y2 receptors by a slowly degradable ATP analog, ATP-gamma-S, was associated with a significant suppression of cell proliferation without affecting the cellular apoptosis. These results indicate that P2Y2 receptors may participate in control of the cell cycle of endometrial carcinoma cells.
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Affiliation(s)
- A C Katzur
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4510, USA
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Tomić M, Zivadinovic D, Van Goor F, Yuan D, Koshimizu T, Stojilkovic SS. Expression of Ca(2+)-mobilizing endothelin(A) receptors and their role in the control of Ca(2+) influx and growth hormone secretion in pituitary somatotrophs. J Neurosci 1999; 19:7721-31. [PMID: 10479676 PMCID: PMC6782447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
The expression and coupling of endothelin (ET) receptors were studied in rat pituitary somatotrophs. These cells exhibited periods of spontaneous action potential firing that generated high-amplitude fluctuations in cytosolic calcium concentration ([Ca(2+)](i)). The message and the specific binding sites for ET(A), but not ET(B), receptors were found in mixed pituitary cells and in highly purified somatotrophs. The activation of these receptors by ET-1 led to an increase in inositol 1,4,5-trisphosphate production and the associated rise in [Ca(2+)](i) and growth hormone (GH) secretion. The Ca(2+)-mobilizing action of ET-1 lasted for 2-3 min and was followed by an inhibition of action potential-driven Ca(2+) influx and GH secretion to below the basal levels. As in somatostatin-treated cells, the ET-1-induced inhibition of spontaneous electrical activity and Ca(2+) influx was accompanied by the inhibition of adenylyl cyclase and by the stimulation of inward rectifier potassium current. In contrast to somatostatin, ET-1 did not inhibit voltage-gated Ca(2+) channels. During prolonged agonist stimulation a gradual recovery of Ca(2+) influx and GH secretion occurred. In somatotrophs treated with pertussis toxin overnight, the ET-1-induced Ca(2+)-mobilizing phase was preserved, but it was followed immediately by facilitated Ca(2+) influx and GH secretion. Both somatostatin- and ET-1-induced inhibitions of adenylyl cyclase activity were abolished in pertussis toxin-treated cells. These results indicate that the transient cross-coupling of Ca(2+)-mobilizing ET(A) receptors to the G(i)/G(o) pathway in somatotrophs provides an effective mechanism to change the rhythm of [Ca(2+)](i) signaling and GH secretion during continuous agonist stimulation.
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MESH Headings
- Adenylate Cyclase Toxin
- Animals
- Calcium/metabolism
- Cells, Cultured
- Cyclic AMP/metabolism
- Cytosol/metabolism
- Egtazic Acid/pharmacology
- Endothelin-1/metabolism
- Endothelin-1/pharmacology
- Female
- Growth Hormone/biosynthesis
- Growth Hormone/metabolism
- Inositol 1,4,5-Trisphosphate/metabolism
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Nifedipine/pharmacology
- Patch-Clamp Techniques
- Pertussis Toxin
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/physiology
- Rats
- Rats, Sprague-Dawley
- Receptor, Endothelin A
- Receptors, Endothelin/genetics
- Receptors, Endothelin/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Somatostatin/pharmacology
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- M Tomić
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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Koshimizu T, Tomić M, Van Goor F, Stojilkovic SS. Functional role of alternative splicing in pituitary P2X2 receptor-channel activation and desensitization. Mol Endocrinol 1998; 12:901-13. [PMID: 9658396 DOI: 10.1210/mend.12.7.0129] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Although ATP-gated ion channel (P2XR) expression is high among anterior pituitary cells, identification of the receptor subtypes and their selective expression within subpopulations of cell types, as well as their physiological role(s), are incompletely characterized. In this study, we focused on the expression and activity of the P2X2R subtype in anterior pituitary cells. Our results indicate that the primary P2X2R gene transcript in pituitary cells undergoes extensive alternative splicing, with generation of six isoforms. Two of these isoforms encode functional channels when expressed in GT1 or HEK293 cells: the wild-type P2X2R and the spliced isoform P2X2-2R, which lacks a stretch of carboxyl-terminal amino acids (Val370-Gln438). Four other clones showed different alterations, including an interfered reading frame starting in the first transmembrane domain and a 27-amino acid deletion in the large extracellular loop. When expressed separately or in combination with wild-type channels, these clones were nonfunctional. In single cell Ca2+ current and cytosolic Ca2+ concentration ([Ca2+)i) measurements, the P2X2R and P2X2-2R had similar EC50 values for ATP and time courses for activation and recovery from desensitization but differed significantly in their desensitization rates. The spliced isoform exhibited rapid and complete desensitization, whereas the wild-type channel desensitized slowly and incompletely. The mRNAs for wild-type and spliced channels were identified in enriched somatotroph, but not gonadotroph or lactotroph fractions. Expression of a functional ATP-gated channel in somatotrophs was confirmed by the ability of ATP to increase the frequency of [Ca2+]i spikes in spontaneously active cells or initiate spiking in quiescent cells. When voltage-gated Ca2+ influx was blocked, ATP increased [Ca2+]i, with a similar profile and EC50 to those observed in GT1 cells heterologously expressing wild-type or spliced P2X2R. The ligand-selectivity profile of native channels was consistent with the presence of P2X2R in somatotrophs. Finally, the desensitization rate of P2X2R in a majority of somatotrophs was comparable to that observed in neurons coexpressing wild-type and spliced channels. These data indicate that alternative splicing of P2X2R and coexpression of P2X2R and P2X2-2R subunits provide effective mechanisms for controlled cationic influx in somatotrophs.
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MESH Headings
- Adenosine Triphosphate/pharmacology
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Base Sequence
- Calcium/metabolism
- Cell Line
- Cell Line, Transformed
- Cells, Cultured
- Cloning, Molecular
- Electric Conductivity
- Female
- Ion Channel Gating
- Molecular Sequence Data
- Pituitary Gland, Anterior/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Purinergic P2/chemistry
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2X2
- Sequence Alignment
- Sequence Analysis, DNA
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Affiliation(s)
- T Koshimizu
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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20
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Koshimizu T, Tomić M, Koshimizu M, Stojilkovic SS. Identification of amino acid residues contributing to desensitization of the P2X2 receptor channel. J Biol Chem 1998; 273:12853-7. [PMID: 9582314 DOI: 10.1074/jbc.273.21.12853] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The P2X2 receptor (P2X2R) is a member of the ATP-gated ion channels that mediate Ca2+ entry in several tissues, including the brain, adrenal medulla, and pituitary. Alternative usage of cryptic splice sites in the primary P2X2R transcript accounts for the existence of several transcript types, one of which (P2X2-2R) encodes a functional channel. P2X2-2R lacks a stretch of cytoplasmic C-terminal amino acids (Val370-Gln438) and exhibits rapid and complete desensitization, whereas P2X2R desensitizes slowly and incompletely. The role of the C terminus in P2X2R desensitization was studied by generating several channel mutants and monitoring intracellular free Ca2+ changes in transfected single GT1-7 neurons. Deletion studies indicated that the Arg371-Ile391 segment of the P2X2R is required for sustained Ca2+ influx. To identify the important residues within this segment, three contiguous amino acids were sequentially changed to alanine. Only two of these replacement mutants, at Arg371-Thr372-Pro373 and Lys374-His375-Pro376, had an enhanced rate of desensitization. Single amino acid deletions in the P2X2R C terminus and a series of insertions of wild-type sequences into the corresponding spliced site identified four residues, Pro373-Lys374-His375-Pro376, required for sustained Ca2+ influx through agonist-occupied wild-type channels. Thus, it is likely that the Pro373-Pro376 sequence of P2X2R represents a functional motif that is critical for the development of the slow desensitization profile observed in these channels. Consequently, deletion of this motif by alternative splicing provides an effective mechanism for generating a channel with controlled Ca2+ influx.
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Affiliation(s)
- T Koshimizu
- Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA
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21
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Koshimizu T, Saitoh K, Mitsuhata H, Konishi R, Inoue S, Shimizu R. [Massive bleeding from the ruptured liver and the inferior vena cava controlled with autotransfusion and cerebral ischemia treated with mild hypothermia]. Masui 1997; 46:978-82. [PMID: 9251518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A patient suffered massive bleeding from the ruptured liver and laceration of the inferior vena cava due to traffic accident, and developed hypotension and decreased level of consciousness. The patient was transferred to our hospital for an emergency operation against intra-abdominal massive bleeding. This massive bleeding was controlled with autotransfusion using washing salvaging autotransfusion device (Cell Savor). Suspected brain ischemia was treated with intended mild hypothermia. When blood pressure decreased to 30 mmHg of systolic pressure over 7 minutes during the operation, suggesting the possible brain ischemia, mild hypothermia was maintained at 33.8 degrees C. Total bleeding volume was 16,700 ml, and total transfused volume was 10,700 ml. Of total transfused volume, 4,500 ml was washed salvaged blood using the intraoperative autotransfusion device. No neurological deficit was found during the postoperative course. The patient was discharged uneventfully on the 20th postoperative day. In conclusion, intraoperative autotransfusion with washed salvaged blood is a useful method for treatment of massive bleeding, and mild hypothermia is efficacious for protecting the brain from ischemia resulting from accidental hypotension.
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Affiliation(s)
- T Koshimizu
- Department of Anesthesiology, Jichi Medical School, Tochigi
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22
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Koshimizu T, Tsujimoto G, Ono K, Masaki T, Sakamoto A. Truncation of the receptor carboxyl terminus impairs membrane signaling but not ligand binding of human ETB endothelin receptor. Biochem Biophys Res Commun 1995; 217:354-62. [PMID: 8526934 DOI: 10.1006/bbrc.1995.2784] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human ETB endothelin receptor (hETBR) is a heptahelical G-protein-coupled receptor consisting of 442 amino acids whose carboxyl (C)-intracellular region has four and twelve sites for potential palmitoylation and phosphorylation, respectively. In order to elucidate the functional roles of these modification sites, we constructed a series of C-terminal truncated hETBRs and expressed them in Ltk- cells. All the truncated hETBRs showed ligand-binding profiles similar to those of the wild-type hETBR. The truncated receptors holding Cys-402 retained both normal intracellular calcium ([Ca2+]i) response and its rapid desensitization; however, the deleted receptors lacking Cys-402 failed to induce the [Ca2+]i response. These results showed that Cys-402 of hETBR is necessary for its intracellular calcium signaling and that at least ten of twelve putative phosphorylation sites are irresponsible for the agonist-induced desensitization.
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Affiliation(s)
- T Koshimizu
- Department of Molecular and Cellular Pharmacology, National Children's Medical Research Center, Tokyo, Japan
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23
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Abstract
Ontogenic expression of somatostatin (SRIF) -messenger RNA (mRNA) in the gastrointestinal tract was examined in neonatal rats aged from 1 day preterm to 60 days postpartum in comparison with that in the hypothalamus. SRIF-mRNA in the hypothalamus was already expressed in prenatal rats and its developmental change was relatively small. In contrast, a unique pattern of SRIF-mRNA expression was seen in the different intestinal regions, gastric antrum, duodenum, jejunum and colon. In the duodenum, SRIF-mRNA level was low at birth, markedly increased during the postnatal 3 days and declined to the previous level by day 21. Jejunal SRIF-mRNA was found in neonates but progressively decreased in a similar way to duodenum. On the contrary, gastric SRIF-mRNA level, which was low during early development, rose rapidly to a peak on day 21 and gradually declined to an adult level. In the colon age-related change was not conspicuous, remaining at a low level. These results indicate that (1) expression of SRIF gene in the intestinal tract is regulated by local factor(s) as well as developmental stage, and (2) shift of SRIF-mRNA pattern occurs during weaning from the duodenum-dominant infantile pattern to the gastric-dominant adult pattern.
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Affiliation(s)
- X Y Yin
- Department of Pediatrics, Kitasato University, School of Medicine, Sagamihara, Japan
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24
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Iwata Y, Amemiya K, Uchida K, Okajima H, Kuramoto H, Kenjo T, Koshimizu T, Kosuge O, Gotoda Y, Saito M. [Statistical analysis of trophoblastic disease in Kanagawa prefecture]. Nihon Sanka Fujinka Gakkai Zasshi 1989; 41:48-54. [PMID: 2538525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two thousand one hundred and thirty-five cases of trophoblastic disease were registered in Kanagawa Prefecture in 7 years (from 1978 to 1984). The incidence of trophoblastic diseases, hydatidiform mole, partial mole, invasive mole, choriocarcinoma and persistent trophoblastic disease (PTD) was 3.22, 1.67, 1.20, 0.07, 0.06 and 0.20, respectively, per 1,000 live births. The incidence was constant for 7 years, and did not differ significantly from that of 16 prefectures in Japan. In Kanagawa, the incidence of hydatidiform mole was less and that of partial mole was more than those in the 16 prefectures. The incidence of invasive mole and choriocarcinoma was lower and that of PTD was higher than those in the 16 prefectures. Total incidence of invasive mole, choriocarcinoma and PTD was higher in the western part of Japan, and lower in the eastern and northern parts. Kanagawa Prefecture is between these two regions. The distribution by age of hydatidiform mole was high in 25-29 y.o. and over 40 y.o. The distribution by age of partial mole tended to be similar to that of hydatidiform mole, but less remarkable. The distribution by age of invasive mole and choriocarcinoma had 2 peaks of 30-34 y.o. and 45-49 y.o. The distribution by age of PTD was between that of hydatidiform mole and choriocarcinoma.
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Affiliation(s)
- Y Iwata
- Kanagawa Medical Association of Obstetrics and Gynecology
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25
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Ohtsuka K, Koshimizu T, Ohyama Y, Yokota Y. [The development of immunoreactive corticotropin-releasing factor (IR-CRF) in the hypothalamus, pancreas and gastrointestinal tract of immature rats]. Nihon Naibunpi Gakkai Zasshi 1986; 62:34-44. [PMID: 3486137 DOI: 10.1507/endocrine1927.62.1_34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Corticotropin-releasing factor (CRF), a hypothalamic releasing hormone, is now known to be widely distributed in extrahypothalamic tissues such as the pancreas and gastrointestinal tract. There are, however, no data concerning the development of CRF in the gastrointestinal tract in immature animals. Using a specific RIA technique for rat CRF, we have determined the IR-CRF concentrations in acid extracts of hypothalamic, pancreatic and gastrointestinal tissues in immature rats. Gel filtration of the extracts was also undertaken in order to investigate the molecular characteristics of the IR-CRF in the digestive system. Pregnant rats were decapitated at 20 days of gestation and the male fetuses (1 day before birth) were removed by hysterotomy. The male pups were also killed by decapitation immediately after birth and at 1, 3, 7, 14, 21, 28 and 42 days postnatally. The rats older than 3 days were divided into fed and 15-h-fasted groups. Pups were weaned at 21 days. The hypothalamus, pancreas, gastric antrum, duodenum and proxymal jejunum were removed immediately after decapitation. The individual tissue fragments were homogenized in 2N acetic acid and boiled for 5 min. The homogenates were centrifuged at 15,000g at 4 degrees C for 30 min and supernatants were removed, lyophilized and stored frozen until assay. Gel filtration was performed at 4 degrees C on a Sephadex G-50 (fine) column (1.6 X 82 cm). A 3 ml of sample was applied to the column and eluted with 0.2N acetic acid containing 0.25% BSA. Fractions of 3 ml were collected and stored at -20 degrees C until assay. The reagents for RIA were purchased from Peninsula Lab., INC. (Belmont, CA.). 125I-Tyr degrees-rat-CRF was labelled by chloramine-T method. Rabbit anti-CRF serum was used at the final dilution of 1:33,000. The antigen bound antibody was separated from the free antigen by the double antibody method using goat anti-rabbit IgG serum. The sensitivity of this RIA was 2-4 pg/tube. The average coefficients of variation for interassay and intraassay were 11.2% and 9.0%, respectively. Extracts of the pancreas, duodenum and jejunum of immature rats gave dilution curves that were parallel to the rat CRF standard curve as well as that of the hypothalamus.(ABSTRACT TRUNCATED AT 400 WORDS)
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26
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Koshimizu T, Ohyama Y, Yokota Y, Ohtsuka K. Peripheral plasma concentrations of somatostatin-like immunoreactivity in newborns and infants. J Clin Endocrinol Metab 1985; 61:78-82. [PMID: 3998074 DOI: 10.1210/jcem-61-1-78] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Postprandial peripheral plasma concentrations of somatostatin-like immunoreactivity (SLI) were measured by RIA after extraction with acetone-petroleum ether in 98 normal newborns and infants. In 62 subjects, plasma concentrations of gastrin were determined simultaneously. The plasma levels of SLI increased progressively with age during the neonatal period. The mean plasma levels of SLI increased significantly from 19.5 +/- 7.5 (+/- SD) pg/ml in 29 cord blood samples to 29.0 +/- 17.2 pg/ml in 36 newborns aged 1-5 days. The mean postprandial level of plasma SLI was significantly higher in 18 infants aged 1-3 months (45.5 +/- 25.8 pg/ml) than in newborns and tended to decrease in infants aged 7-10 months after weaning (31.6 +/- 7.9 pg/ml). The mean postprandial levels of plasma SLI were significantly higher in newborns and infants less than 10 months old than in older children aged 8-12 yr (10.2 +/- 3.7 pg/ml). The gel filtration patterns of SLI of plasma extracts were similar in infants and older children. The changing pattern of mean plasma gastrin with age was similar to that of SLI, and individual plasma levels of SLI were significantly correlated with those of gastrin during the neonatal period. High concentrations of SLI are present in the peripheral circulation during the first 10 months of life. Thus, this peptide may play a significant role as a hormone in nutrient homeostasis in infants.
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Abstract
Using a specific RIA technique, we have determined the somatostatin-like immunoreactivity (SLI) concentrations in acid extracts of pancreatic and gastrointestinal tissues and studied their relationships to feeding in fed and 15-h-fasted immature (less than 24 days old) rats. Mean pancreatic SLI concentrations per unit of protein were low before and immediately after birth before the initiation of feeding. They increased 7-fold during the first 3 days and remained high for the next 2 weeks. Gastric SLI concentrations were also low before and immediately after birth and increased progressively with age up to day 21 (time of weaning), followed by an abrupt increase at day 24, especially in 15-h-fasted rats. The mean SLI concentrations in the duodenum and jejunum were 4.9-6.3 times higher than that in the gastric antrum 1 day before birth and were also significantly higher than those in the gastric antrum for the first 3-7 days. No significant difference was found by age in the gel filtration patterns of tissue extracts from the pancreas, gastric antrum, and duodenum in fetal and fasted 3- and 24-day-old rats. I conclude from these findings that: 1) the developmental patterns of pancreatic and gastrointestinal SLI show a close relationship with feeding, suggesting the important role of somatostatin in the digestive functions and nutrition in immature rats, and 2) the quantitative distribution of somatostatin in the gastrointestinal tract markedly differs so that there is intestinal predominance in fetal or neonatal rats, and predominance in the stomach in adult rats.
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28
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Koshimizu T, Kato K, Shimizu N, Hibi I, Suwa S. [A review of 74 cases of precocious puberty treated with cyproterone acetate in Japan (author's transl)]. Nihon Naibunpi Gakkai Zasshi 1981; 57:42-63. [PMID: 6453732 DOI: 10.1507/endocrine1927.57.1_42] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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29
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Ishii H, Koshimizu T, Usami S, Fujimoto T. Toxicity of aspartame and its diketopiperazine for Wistar rats by dietary administration for 104 weeks. Toxicology 1981; 21:91-4. [PMID: 7281205 DOI: 10.1016/0300-483x(81)90119-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Aspartame (APM) or L-aspartyl-L-phenylalanine, and a 3 : 1 combination of APM with its decomposition product, 5-benzyl-3,6-dioxo-2-piperazine acetic acid (DKP), were incorporated at levels of up to 4 g/kg in the diet of male and female Wistar rats from 6 weeks to 104 weeks of age. There was a dose-dependent depression of body weight gain at 2 and 4 g/kg AMP and at 4 g/kg APM + DKP in males, and at all dose levels in females, correlated with decreased food consumption and attributed to liberation of amino acids from hydrolysis of APM. Increases in urinary specific gravity and pH, with increase of relative kidney weight, were attributed to the urinary excretion DKP and acidic metabolites of APM. A dose-related increase in urinary calcium probably reflected increased calcium absorption, as from high protein diets. A slight decrease in serum cholesterol and an increase in relative spleen weight appeared to be without adverse effect. It is concluded that the treatments were without toxic effect.
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Koshimizu T. Plasma renin activity and aldosterone concentration in normal subjects and patients with salt-losing type of congenital adrenal hyperplasia during infancy. Clin Endocrinol (Oxf) 1979; 10:515-22. [PMID: 225066 DOI: 10.1111/j.1365-2265.1979.tb02109.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Koshimizu T. [Determination of serum dehydroepiandrosterone sulfate in children and its clinical significance]. Horumon To Rinsho 1978; 26:1120-5. [PMID: 152682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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32
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Koshimizu T. [Effects of cyproterone acetate on the pituitary-gonadal system and other endocrine functions in female idiopathic precocious puberty]. Horumon To Rinsho 1977; 25:989-97. [PMID: 923124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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33
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Koshimizu T, Oyama S, Mihara T, Kudo Y, Fujisawa Y. [Age-related changes of serum testosterone, estrogens, LH and FSH from birth to puberty, and sex differences in the maturation of hypophyseal-gonadal system in childhood]. Horumon To Rinsho 1975; 23:1239-47. [PMID: 1240040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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34
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Terayama Y, Kizaki M, Sato S, Koshimizu T. [Reliability and advantages of serum aldosterone RIA by sephadex LH-20 reversed-phase partition chromatography]. Horumon To Rinsho 1975; 23:731-7. [PMID: 1170995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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35
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Hiraishi S, Oyama S, Koshimizu T. [Hypoparathyroidism in an infant of a mother with hyperparathyroidism due to parathyroid neoplasm]. Horumon To Rinsho 1975; 23:569-73. [PMID: 1170976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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36
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Koshimizu T, Kato K. [Short stature and genes]. Horumon To Rinsho 1972; 20:261-9. [PMID: 4561537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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37
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Takakura I, Kato K, Koshimizu T, Camacho R, Uylangco C. Study of the adrenocortical reserve function in paediatric cholera patients. Bull World Health Organ 1972; 46:27-32. [PMID: 4337629 PMCID: PMC2480632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The adrenocortical reserve function of 20 cases of paediatric cholera was studied by intravenous ACTH tests. The findings indicate the presence of adrenocortical hyperactivity, and the poor response to ACTH stimulation shows that the adrenocortical reserve in these cases had been already stimulated to the maximum extent by salt depletion at the time of admission. These findings do not support the value of adrenocortical hormone treatment in cholera.
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38
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Okajima A, Sugiura M, Koshimizu T, Kato S. [3 cases of Down's syndrome with hyperthyroidism]. Horumon To Rinsho 1971; 19:233-8. [PMID: 4255701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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39
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Tsuji A, Koshimizu T, Kato K. [Non-fatal case of neonatal thyrotoxicosis with serial determination of LATS]. Horumon To Rinsho 1970; 18:417-20. [PMID: 5465536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Takakura I, Koshimizu T, Kato K. [On the adrenocortical reserve test for infants using synthetic ACTH]. Horumon To Rinsho 1968; 16:260-6. [PMID: 4300337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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