Prevalence and Characterization of Thyroid Hemiagenesis in Japan: The Fukushima Health Management Survey.

BACKGROUND: Thyroid hemiagenesis is a rare congenital variant characterized by the lack of development of one thyroid lobe with no clinical manifestations. METHODS: This study was performed to determine the prevalence and characteristics of thyroid hemiagenesis in a normal Japanese population. This cross-sectional study was performed from October 9, 2011, to April 30, 2015. In total, 299,908 children and young adults in the Fukushima Health Management Survey were examined to determine the presence of thyroid agenesis or hemiagenesis. Thyroid width, thickness, and length were measured in 292,452 of these subjects. RESULTS: Thyroid agenesis was diagnosed in 13 subjects, and hemiagenesis was detected in 67 subjects (0.02%; 22.3/100,000 individuals). Although there was no significant sex-related difference (p = 0.067), the female:male ratio was 1.67:1.00. Females were significantly dominant in right hemiagenesis, while there was no difference in left hemiagenesis between males and females. The thyroid volumes at the 2.5th and 97.5th percentiles for age and body surface area were determined for each sex. Multivariate regression analysis showed that a large hemithyroid volume was independently associated with the presence of contralateral hemiagenesis (p < 0.001). CONCLUSION: The prevalence of thyroid hemiagenesis in the present study is in agreement with that reported in other countries. The prevalence of right hemiagenesis was higher in females, and the larger contralateral lobe in patients with rather than without hemiagenesis may have been caused by a compensatory feedback mechanism to prevent hypothyroidism. In addition, the prevalence of hemiagenesis, especially right hemiagenesis, may be affected by sex-related factors similar to those in patients with an ectopic thyroid gland.

[Sanitary assessment of radon hazards in residential buildings]. / Gigienicheskaia otsenka opasnosti radona v zhilykh pomeshcheniiakh.

The authors have constructed models including that of dose-effect of the content of decay products, that of the volumetric activity of radon in the apartments, and that of biological human responses. They have found specific features of female reproduction dysfunction, perinatal, general, and cancer morbidity and mortality. The maximum ineffective radon concentration upon chronic exposure has been established by using dosage simulation of the frequency of genetic disorders (small malformations).

[Experimental assessment of adaptive possibilities after chronic prenatal exposure to gamma irradiation at various absorbed doses]. / Eksperimental'naia otsenka adaptivnykh vozmozhnostei organizma posle antenatal'nogo khronicheskogo deistviia gamma-izlucheniia v raznykh pogloshchennykh dozakh.

The purpose of the investigation is the study of dose-response relationship at the antenatal exposure of low level ionizing radiation (137Cs, 1.0-1.25; 1.7-1.9 and 2.3-2.5 Gy during 20 days). The decrease of body weight in pregnant females and antenatal embryonic mortality at the doses 2.3-2.5 Gy are revealed. Physical postnatal anomalies with decrease of the adaptation were estimated by the strength endurance after antenatal exposure of gamma-rays at the doses of 1.0-2.5 Gy.

1992 assessment of radiation risk from dental radiography.

Recent studies suggest that the lifetime cancer risks from exposure to low levels of ionizing radiation may be greater than previously estimated. This review first summarizes the findings of these studies as they pertain to dental radiology, then uses their concepts in combination with dosimetry from the dental literature to estimate the radiation risk from dental radiology. Estimation of risk from groups of exposed individuals requires use of mathematical models that fit the epidemiological data. The ICRP estimates that a single brief whole-body exposure of 1 Gy to 10,000 people results in about 500 additional cancer deaths over the lifetime of the exposed individuals, assuming a dose rate effectiveness factor of 2 for cancers other than leukaemia. Leukaemias are seen as a wave from 5 to 30 years following exposure. Cancers other than leukaemia typically start to appear about 10 years following exposure and remain in excess for as long as most exposed populations are followed, presumably for the lifetime of the exposed individuals. The gonadal dose is so small from dental radiography that the risk of heritable defects is negligible in comparison with the somatic risk. The dental literature contains several studies reporting sufficient dosimetric data for radiosensitive sites in the head and neck to allow estimation of the risk of fatal cancers from intra-oral and panoramic radiography. The highest estimated risks (using the ICRP data) are for leukaemia (bone marrow), thyroid and bone surface cancer. The total risk is estimated to be 2.5 fatal malignancies per 10(6) full-mouth examinations made with D-speed film and round collimation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Environmental pollution and congenital abnormalities according to the data of environmental health monitoring]. / Zagriaznenie okruzhaiushchei sredy i vrozhdennye poroki razvitiia po materialam gigienicheskogo monitoringa.

Study of the environmental pollution (ambient air, drinking water, food and fodder) in southern Ukraine industrial region and study of congenital developmental defects were carried out. 78,678 newborns were examined. The most significant environmental factors responsible for congenital developmental defects, as authors proposed, were the ambient air pollution and environmental radioactivity.

Radiation exposure of fertile women in medical research studies.

Fertile women may be exposed to ionizing radiation as human subjects in medical research studies. If the woman is pregnant, such exposures may result in risk to an embryo/fetus. Fertile women may be screened for pregnancy before exposure to ionizing radiation by interview, general examination, or pregnancy test. Use of the sensitive serum pregnancy test has become common because it offers concrete evidence that the woman is not pregnant (more specifically, that an embryo is not implanted). Evidence suggests that risk to the embryo from radiation exposure before organogenesis is extremely low or nonexistent. Further, demonstrated effects on organogenesis are rare or inconclusive at fetal doses below 50 mSv (5 rem). Therefore, there may be some level of radiation exposure below which risk to the fetus may be considered essentially zero, and a serum pregnancy test is unnecessary. This paper reviews the fetal risks and suggests that consideration be given to establishing a limit to the fetus of 0.5 mSv (50 mrem), below which pregnancy screening need not include the use of a serum pregnancy test.

[Drug use and ionizing radiation in early pregnancy. Risk assessment and postpartum results]. / Medikamenteneinnahme und ionisierende Strahlen in der Frühgravidität. Risikobeurteilung und postpartale Ergebnisse.

The influence of medical drugs and X-rays upon early pregnancy causes problems of great responsibility for the physician. He is supposed to grant optimum consultation to the anxious women who finally have to decide to carry on their pregnancy or not. This topic is difficult to value as controlled prospective studies are not practicable for ethical reasons, and the results of animal experiments are rarely transferable to human medicine. In this paper the facts and data of our consulting activities are summarized from April 1985 to May 1986 in the sense of a prospective study. Over all 64 consultations were performed in these 14 months, up to now 30 women have been delivered of a newborn. The procedure and the principles of our consultations and the postnatal results are presented below.