Identical twins

A typical noisy light based CRS experiment involves the splitting of a noisy beam (short autocorrelation time, broadband) into identical twin beams, B and B, tlnough the use of a Michelson interferometer. One ami of the interferometer is computer controlled to introduce a relative delay, x, between B and B. The twin beams exit the interferometer and are joined by a narrowband field, M, to produce the CRS-type third order polarization in the sample ([Pg.1209]

Joseph Murray performed the first successful organ transplant in 1954, a kidney transplant between identical twins.1 This was a success in large part because no immunosuppression was necessary since the donor and recipient were genetically identical. Murray s success led to attempts with other organs over the next 20 years (Table 52-1). 

The influence of genetics in leukemia is supported by several observations. For example, among identical twins, the occurrence of ALL is associated with a 20% to 25% chance of the disease developing in the other twin within 1 year. In fraternal twins, there is a fourfold increase in the risk of leukemia compared with the normal population. Additionally, leukemia is known to be increased in several chromosomally abnormal populations. Patients with Down s syndrome have a 20 times increased risk of developing leukemia compared with the rest of the population. Patients with Klinefelter s syndrome and Bloom s syndrome also have an increased incidence of leukemias.7... 

For an allogeneic HCT, the recipient and the donor are dissimilar genetically unless they are identical twins (referred to as a syngeneic HCT). The tissue transplanted is immunologi-cally active, and thus there is potential for bidirectional graft... 

Nagao T, Mauer AM. Concordance for dmg-induced aplastic anemia in identical twins. N Engl J Med 1969 281[1] 7—11-... 

Wilson SB et al. Multiple differences in gene expression in regulatory V24JQ T cells from identical twins discordant for type I diabetes. Proc Natl Acad Sci USA 2000 97 7411-7416. 

Genetics clearly play a role in obesity. It has been noted that an adopted child s body weight is usually more similar to the body weight of his or her biological parents than that of his or her adopted parents. Identical twins usually have similar occurrences of obesity. Studies have also shown that fraternal twins do not show this same likelihood of obesity when one twin is overweight, the other is very often not. These examples help demonstrate that genetics play a significant role in obesity. 

Tissue/organ transplantation in which the donor is not genetically identical to the recipient (i.e. in cases other than identical twins). The recipient will mount an immune response against the transplanted tissue, culminating in tissue rejection unless immunosuppressive agents are administered. 

With the exception of identical twins, every individual has a unique genetic makeup. Because genetic factors are inherited from our parents, family members tend to have genetic similarities. Sometimes, members of the same racial or ethnic group are also more likely to have some similar genetic characteristics. 

Why would tissue transplanted from father to daughter have a greater risk of being detected as foreign than a tissue transplanted between identical twins ... 

The functional requirement specification (FRS) and its nearly identical twin, the user requirement specification (URS), is a list of functions and features the device should process. If there are specific needs the customer (user) has then this is the place to include it. The level of specificity may be dependent on the experience the end-user has with dissolution. An experienced dissolution scientist will be sensitive to issues such as cross-contamination or the importance of timing etc. Critical specifications need to be clearly stated since the FRS serves as the starting point of the test plan (discussed in the next section). 

Everyday experience shows us that all human beings are unique in their external appearance and can be safely distinguished if only sufficient independent physical traits are compared. From so-called identical twins we learn that a considerable part of this phenotype is inherited. 

Bouchard, T. J., Jr. (1982). [Review of Identical twins reared apart A reanalysis]. Contemporary Psychology, 27, 190-191. 

It will be noted that the two identical twins included in the study exhibit patterns which show a strong resemblance, but that each of the other patterns is distinctively different. This study was made with the idea of individual differences definitely in mind the intraindividual as well as the inter-individual differences were carefully studied statistically and otherwise. The graphs in Figure 13 represent averages for each individual the number of samples in a few cases was as low as 7 to 12, but more often it was 25 to 50. Such results as these have been obtained so many times in our laboratory that there can be no possible question as to the distinctiveness of the urine of each individual. 

Our evidence leads us to conclude, however, that these patterns tend to remain about the same in reasonably well individuals, at least over a period of years. That very young babies have highly distinctive patterns and that closely inbred strains of rats have close resemblances in their patterns (as do also human identical twins) strongly indicate that the pattern which an adult human being exhibits has not been produced merely as a result of the various illnesses and environmental experiences through which he has passed. 

Syngeneic Transplant The person donating the bone marrow or stem cell is an identical twin. 

Somatic mutations may occur in MZ twins after the cleavage event that forms them, causing identical twins to be at least somewhat different genetically. 

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