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Critism of psychology Fourm |
Malformation of Embryo/Fetus due to radiation exposure By Sharmila Sanmuganithi Radiation exposure can lead to lethal malformations of embryo or fetus. This can be due to either therapeutic or inevitable atmosphere exposure. There are two reasons why the embryo is known to be affected more by radiation. First, embryo cells are rapidly dividing and radiosensitive. Second, since the embryo consists of small number of cells during their very early stages of life, each cell is vital to the development of the fetus. All physical and psychological defects of radiation are strongly dependent on three factors such as development stage, radiation dose and radiation dose-rate. There are few number studies completed to examine the effect of radiation on the fetus, such as Brain damage in Utero Project of Chernobyl accident, New England Cancer Death Study, Animal and Human Study done by Beir V, and New York Tinea Capitis Study. Radiation exposure normally leads to death and abnormal development in the fetus, and this issue was clearly proved by the Brain damage in Utero Project of Chernobyl Accident. This utero project was done at the explosion of the Chernobyl nuclear reactor in Ukraine in 1986. Study was setout to examine all children born within a year whose mothers were evacuated within 30km of the reactor or mothers who lived in the Strictly Controlled Zones. The assessments and protocols were made to find precise information on mental retardation, cognitive impairment, anthropometric measurements, neurological and endocrinological assessment and brain-mapping. Findings show the incident of higher mental retardation, emotional and behavioural problems, border-line nervous and psychological disorder among exposed children. (Health consequences of the Chernobyl accident summary report”, WHO 1995, 19-30) According to human study done by Ritenour, R.(elaborate), radiation exposure on the fetus can lead to neonatal death, intrauterine growth retardation (IUGR), and congenital malformation. Due the exposure embryo is also more susceptible to leukemia. (Health Effects of Low-Level Radiation, 1984. 13-22). Data from atomic bomb survivors also confirmed abnormalities such as microcephaly or small head size. There are many genetic defects also found such as carcinogenicity, infrequent mutation, abnormal growth and mortality due to the exposure. According to a study done by Max L. Baker et al on “Radiation and the fetus”, the period of organogenesis is very radiosensitive than other developmental stages. Overall, the physical size of the person would be reduced, and this has been confirmed by the mouse experiment done Max L. Baker et al. Data also suggest that utero radiation exposure will increase the likelihood of cancer by as much as 50 percent, and the cancer mostly involved is leukemia and tumors of the CNS. According to Webster, E. et al. on “A Primer on low-level ionizing radiation and its biological effects”, the developmental defects were observed in X-rays and stated as one of the first agent to produce dreadful effects on the fetus. During the 1920’s pregnant women who had received therapeutic irradiation of the abdomen were examined and results showed unusual malformed children. Here are some of the reported human abnormalities after larger radiation exposure in utero such as growth retardation (microcephaly- small head size), blindness ( microphthalmia- small eyes), mongolism (hydrocephaly- abnormal fluid in brain), skull malformation (chorioretinitis-eye inflammation), skeletal abnormality (strabismus–eye deprivations), mental retardation (coordinated defects), and ear abnormalities (genital deformities). Webster, E. et al. also mentioned that childhood cancer following fetal exposure is several times greater than the risk of cancer induction in adult from the same radiation dose. In “Health Effects of Exposure to Low levels of Ionizing Radiation” by Beir, V., the effects of X- ray utero exposure were examined by closely following cancer deaths in 1,429,400 children born between 1940 and 1960 in 42 New England hospitals. Findings showed an excessive of cancers among those exposed to diagnostic X-rays in utero. Cancer also appeared to be increased in prenatally exposed atomic-bomb survivors more than four decades after they were irradiated, and it remains to be established that the risk of cancer in adult life is increased by prenatal irradiation. Thus, these results clearly confirm that susceptibility to radiation induced cancer is higher in prenatally exposed survivors than in postnatally exposed survivors. The effects of prenatal irradiation on the growth and development of the mammalian embryo was examined in an animal study done by Beir, V. The results showed direct radiation injury of developing tissue, including gross structural malformations, growth retardation, embryo lethality, sterility, and central nervous system abnormalities. Major anatomical malformations have been produced in all mammalians species by irradiation of the embryo during early organogenesis. In experimental animals, the central nervous system malformations most likely to be produced by irradiation during early organogenesis include hydrocephaly, anencephaly, encephalocele, and spina bifida. There were other functional and behavioural effects also found in mouse and monkeys such as motor defects, emotionality, impairment of nervous reflexes and hyperactivity and deficit in learning. Beir V also had done a human study in order to prove the effects of radiation exposure. Data concerning the effects of prenatal irradiation are those to brain development. Severe mental retardation and small head size increases with increasing exposure in recent studies based on a cohort of 1,598 such individuals, all of the 30 children who were found to have severe mental retardation was diagnosed before age of 17, other health problems include neonatal jaundice, neurofibromatosis, Down syndrome and encephalitis. The epidemiologic data has identified the maximal sensitivity of the human brain to occur between 8 and 15 weeks of gestational development. At 16-25 weeks after conception, differentiation accelerates, synaptogenesis, producing a functional deficit in the brain connections. The response seen among the atomic-bomb survivors, irradiated during the period 16-25 weeks after conception. Intelligence test scores of individuals of 10-11 years of age who were exposed prenatally to the Hiroshima and Nagasaki atomic bombs have been analyzed, and there was a progressive downward shift in individual scores with increasing exposure was observed. According to New York Tinea Capitis Study, Albert et al. reported that children in New York, treated for tinea capitis by X irradiation, had a higher incidence of treated psychiatric disorder than those treated with chemotherapy. Children also had lower examination scores on scholastic aptitude, intelligence quotient, and psychological tests, completed fewer school grades, had increased admissions to mental hospitals for certain neuropsychiatric diseases, and had a slightly higher frequency of mental retardation. Acute side effects due to radiation exposure There are many different types of acute side effects after the radiation exposure, and these exposures can either from the atmosphere or from therapeutic treatments as X-rays or radiation treatment for cancer. These effects depend on the part of the body that get treated and the amount of tissue that receive radiation. After radiation treatment patient may feel radiation nausea, fatigue, irritation or inflammation of skin, dry mouth and loss of taste. Radiation exposure can also lead to hair loss, weight loss, low blood count and malformations in accessory or mucous membrane. Patients who go through radiation therapy experience nausea after treatment, and the degree of vomiting depends on the amount of exposure. To compensate the fluid loss, patients are encouraged to drink water. Hair loss/ Alopecia can occur throughout the body, but it is not permanent. Areas of hair loss include head, pubic area, face, arms, legs and underarm. This can also lead to emotional and psychological abnormalities. After the radiation exposure one may feel dizzy or fatigue and lack of energy can also be felt. Fatigue varies from person to person. Radiation exposure at bone marrow can lead to low blood count by reducing the number of white blood cells and platelets, and it can also damage lymphocytes or lymph nodes. Defects in mucous membrane occur due to radiation exposure in mouth, pharynx, esophagus, trachea, bowel, bladder or rectum. Mucositis may develop after radiation treatment and it breaks down rapidly dividing epithelial cells lining GI tract. As a result of Mucositis, one can expose to ulceration or infection at GI tract. The other acute side effects include dysphagia, hoarseness, tracheitis, dysuria, diarrhea and abdominal cramps. Radiation exposure in accessory glands such as salivary or mucous producing glands can lead to oral discomfort, dryness, change in taste, cough and urinary or bowl syndromes. Reference:
1.American Cancer Society .“Possible Side Effects of Radiation
Therapy.”. January 23, 2007. <http://www.cancer.org/docroot/ETO/content/ETO
_1_4X_ Side_ Effects_of_ radiation_Therapy.asp?sitearea=ETO>
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