Invited Review Articles
Focal Macular Electroretinography
YOZO MIYAKE
pg(s) 79- 84
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Over the last two decades, many attempts have been made to record electroretinograms (ERG) of human macula by several investigators. However, previous ERG responses were not informative enough, because each ERG component could not be evaluated independently. However, we have developed a new system for recording focal macular ERG where we can evaluate all ERG components. This paper reviews what we have found using our system in terms of the macular physiology and pathogenesis in human eyes.
Physiological Roles of Placental Proteases in Feto-Placental Homeostasis
SHIGEHIKO MIZUTANI
pg(s) 85- 95
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Although many proteases exist in human placenta, their physiological roles are still largely unknown. Our studies showed that these placental proteases metabolize vasoactive and immunomodulating peptides, possibly derived from the fetus, and control the exchange of peptide hormones across the placenta in order to maintain feto-placental homeostasis. We clarified the pregnancy serum oxytocinase discovered by Fekete in 1930 and angiotensinase by Page in 1947, respectively. In addition we showed bradykininase in the pregnancy serum. The ratio of peak systolic over least diastolic flow velocity of uterine or umbilical artery assessed by the Doppler technique was closely correlated with the levels of maternal serum proteases in preeclampsia, which suggested that placental proteases might control uteroplacental circulation via the regulation of concentrations of vasoactive peptides in uteroplacental circulation. Thus, changes in maternal serum protease activities were useful for monitoring of pre-elcampsia and predicting the onset of labor. The degradation of immunomodulating peptides by placental protease(s) also suggests the possible involvement of placental protease(s) in the immunological aspect of pregnancy. Recently we have cloned one of the major placental protease, oxytocinase (P-LAP). Its amino acid sequences had 87% homology of rat IRAP so called VP 165. This enzyme was confirmed to co-localize in Glut 4 containing vesicles in rat skeletal muscles and adipocytes. Accordingly PLAP, the human homologue of VP165, may have an intriguing possibility in a variety of events not restricted to the regulation of pregnancy induced phenomena.
Oculocutaneous Albinism and Analysis of Tyrosinase Gene in Japanese Patients
YASUSHI TOMITA and YOSHINORI MIYAMURA
pg(s) 97-102
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Oculocutaneous albinism (OCA) is a heterogeneous groups of autosomal-recessive genetic disorders. The molecular pathogenesis of several types of OCA have been clarified in the ten years since our first report in 1989 on a pathologic mutation of the tyrosinase gene. In this article, a new classification of OCA based on genetic evidence is briefly reviewed, and our study on Japanese patients with tyrosinase-negative OCA is summarized.
Multiple Isoforms of Thyroid Hormone Receptor: An Analysis of Their Relative Contribution in Mediating Thyroid Hormone Action
YOSHIHARU MURATA
pg(s)103-115
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VThyroid hormone is essential for normal development and maintaining metabolic homeostasis. In mediating the thyroid hormone action, the thyroid hormone receptor (TR) plays a key role. Almost one decade ago, the cloning of TR was achieved, revealing the existence of at least two genes, TR alpha and TR beta, which encode TR. From these genes several TR isoforms can be generated by alternative splicing. They are designated as TR alpha 1, TR alpha 2 (inactive form), TR beta 1 and TR beta 2. Since the discovery of these TR isoforms, many studies have attempted to demonstrate their relative contribution to mediate thyroid hormone in various tissues. The distinct tissue distribution and the ontogenic expression of the TR isoforms, and the fact that TR gene abnormalities associated with the syndrome of resistance to thyroid hormone (RTH) have been found only in the TR beta gene, indicate that products of TR alpha and TR beta have distinct roles. However, no direct evidence of the distinct roles of the TR isoforms has been shown. Gene knockouts of either TR isoform would provide important information to understanding their specific roles. In this review, the history of the TR isoform discovery and studies attempting to demonstrate the specific roles of TR isoforms are summarized, and recent reports dealing with knockouts of TR isoforms are comprehensively presented.
Original Papers
Newly Developed Diabetic Retinopathy and Its Preceding Changes in Biological Markers
MASAYO KOJIMA, TAKASHI KAWAMURA, KAZUYO TSUSHITA, YOSHIKO MIZUNO, MASASHI YOKOI, YINGSONG LIN, RIE AOKI, KENJI WAKAI, AKIKO TAMAKOSHI and YOSHIYUKI OHNO
pg(s)117-124
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To disclose the chronological changes prior to the manifestation of diabetic retinopathy (DR), we analyzed the time course of biological markers among apparently healthy diabetic subjects in a case-control study of 21,579 adults who had undergone comprehensive health examinations for > or = 10 years. We identified 54 cases who had newly developed DR, and selected 108 adults without fundus abnormalities, matching them for sex, age, and fasting plasma glucose (FPG) at the onset of the patient group's retinopathy as a referent group from the same population. In a multivariate analysis, a high average FPG (> 175 mg/dl) and a final-year FPG reduction (< -3%) were significantly associated with a 5.4 (95% CI, 1.8-15.7)- and 5.0 (95% CI, 1.0-24.7)-fold increased risk of DR, respectively. Thus, we surmised that sustained hyperglycemia and a subsequent drop in FPG might promote retinopathy in non-insulin dependent diabetes mellitus.
Mesothelial Cell Proliferation in the Scala Tympani: A Reaction to the Rupture of the Round Window Membrane
MICHIHIKO SONE
pg(s)125-130
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The inner layer of the round window membrane is composed of mesothelial cells and this mesothelial cell layer extends to the scala tympani. This study describes the histopathologic findings of temporal bone analysis from a patient with bilateral perilymphatic fistula of the round window membrane. The left ear showed proliferation of mesothelial cells in the scala tympani of the basal turn adjoining the round window membrane. This cell proliferation is thought to be a reaction to the rupture of the round window membrane.
Autologous Blood Transfusion and Hypotensive Anesthesia for Rotational Acetabular Osteotomy
KOICHIRO YOSHIDA, YUKIHARU HASEGAWA, NOBUO KONISHI and HISASHI IWATA
pg(s)131-135
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We employed hypotensive anesthesia with prostaglandin E1 (PGE1) and transfused 400 ml of autologous whole blood on the first postoperative day to avoid homologous blood transfusion in 137 patients undergoing rotational acetabular osteotomy (RAO) and RAO combined with intertrochanteric valgus osteotomy. Four hundred ml of whole blood were donated 1 week before the surgery, and transfused on the first postoperative day after hematological examination. We employed induced hypotension with PGE1 under general anesthesia with enflurane or isoflurane. Intraoperative systolic blood pressure was maintained at approximately 70-80 mmHg. The mean operation time was 139 +/- 32 minutes. The mean intraoperative and the postoperative estimated blood loss was 286 +/- 152 g and 259 +/- 122 g, respectively. The mean hemoglobin content was 13.3 +/- 1.1 g/dl before the operation. It showed the lowest value of 9.4 +/- 1.0 g/dl on the first postoperative day but it returned to 10.4 +/- 1.0 g/dl in the second postoperative week. There was no use of homologous blood transfusion. We consider that the concomitant use of autologous blood donation and hypotensive anesthesia is an extremely useful method to avoid homologous blood transfusion.
Abstracts
Annual Research Meeting for Graduate Students: Nagoya, December 1997
pg(s)137-136
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