Defects, human physical

Manual ultrasonic testing offers the advantages of low equipment cost combined with the flexibility of the human operator to provide good access and complex scanning capability. However, a total reliance on the capabilities of the ultrasonic technician to visualise the physical situation leads to a number of drawbacks, including lack of accuracy and consistency of defect size and location measurements, lack of verification that the required scan coverage has been fully achieved, and lack of consistency in flaw classification. A further disadvantage is that the ultrasonic data is not permanently recorded there is therefore no opportunity for the data to be re-examined at a later date if required. 

In 1963 J.H. Rubinstein and H. Taybi reported a rare human disease that induced mental retardation, an increased risk of neoplasia and physical abnormalities, including broad thumbs, big and broad toes, short stature and craniofacial anomalies. The molecular basis of the Rubinstein-Taybi syndrome (RTS) was later discovered to be a disruption of one copy of the human CREB binding protein (CBP or CREB-BP) gene that encodes the histone acetyltransferase CBP [3]. In addition to CBP, all mammals have a closely related acetyltransferase, p300. Retrospectively, RTS was the first disease found to be due to a defective acetylation process [1-3]. 

While defects in protein XPD often cause typical XP symptoms, some defects in the same protein lead to trichothiodystrophy (TTD, brittle hair disease). The hair is sulfur deficient, and scaly skin (ichthyosis, Box 8-F), mental retardation, and other symptoms are observed.0 Like their yeast counterparts (proteins RAD3 and RAD25), XPB and XPD are both DNA helicases.0 They also constitute distinct subunits of the human transcription factor TFIIHP, which is discussed in Chapter 28. It seems likely that XPD is involved in transcription-coupled repair (TCR) of DNA.° °i-s This is a subpathway of the nucleotide excision repair (NER) pathway, which allows for rapid repair of the transcribed strand of DNA. This is important in tissues such as skin, where the global NER process may be too slow to keep up with the need for rapid protein synthesis. Transcription-coupled repair also appears to depend upon proteins CSA and CSB, defects which may result in the rare cockayne syndrome.13 0 4 11 Patients are not only photosensitive but have severe mental and physical retardation including skeletal defects and a wizened appearance. 

Approximately 1200 chemicals have been shown to be teratogenic in experimental animals. However, less than 40 physical, chemical, or infectious agents are known to produce birth defects in humans (Table 34.3). Five xenobiotics known to be... 

While most cells do not take up naked DNA in the absence of the physical or chemical treatments described above, muscle cells appear to be an exception. Direct injection of free nucleic acids in saline solutions into skeletal and cardiac muscles has been shown to result in prolonged expression (Wolff et al, 1991 Kitsis et al, 1991). By using this method, the 12 kilobase human dystrophin gene, defective in muscular dystrophy patients, has been introduced into the muscle cells of mice (Partridge, 1991 Ascadi et al, 1991). 

This is precisely what characterizes Everyman as the enemy of human differences. He accepts the Other in so far as the Other conforms to his image and conduct. However, if he and the Other differ, he defines the Other as defective—physically, mentally, or morally—and accepts him only if he is able and willing to cast off those of his features that set him apart from the normal. If the Other recants his false beliefs, or submits to treatment for his illness, then, and only then, will he be accepted as a member of the group. If he fails to do these things, the Other becomes the Evil one—whether he be called the Stranger, the Patient, or the Enemy. 

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