Embryonic type

Small hypophyseal and meningeal branches of the ICA are not visible in MR angiographies. The first originating vessel is the ophthalmic artery from the C3 segment. Distally the posterior communicating artery and subsequently the anterior choroidal artery arise from the ICA. A direct origin of the posterior cerebral artery from the ICA is referred to as embryonic type. 

The size of the basilar artery varies markedly. Given an embryonic type of PCA, the basilar artery can be extremely small and sometimes it appears to end at the level of the superior cerebellar arteries. 

Koltgen D, Ceballos-Baumann AO, Franke C. Botuhnum toxin converts muscle acetylcholine receptors from adult to embryonic type. Muscle Nerve 1994 17(7) 779-84. 

Bearing in mind these cautions, the permeability to calcium is around 1/10 to 1/5 of that to sodium or cesium ions for mammalian muscle receptors of the embryonic type (native or recombinant), and is much higher (0.5-0.9) for the adult form of the receptor (133-135). This is in agreement with estimates that calcium ions carry approximately 2% and 4% of the total nicotinic current through embryonic and adult muscle receptors, respectively [at physiological calcium concentrations and holding potentials (136-138)]. 

This drug is used primarily in refractory cases of embryonal-type testicular cancer. 

A large embryonic type of red blood cell with a large nucleus present in the blood in cases of pernicious anemia, vitamin B-12 deficiency, and/or folacin deficiency. 

Upon exposure to retinoic acid (RA), embryonal carcinoma (EC) F9 cells can be induced to differentiate into three distinct extra-embryonic types of... 

Muscle tissue is unique in its ability to shorten or contract. The human body has three basic types of muscle tissue histologically classified into smooth, striated, and cardiac muscle tissues. Only the striated muscle tissue is found in all skeletal muscles. The type of cells which compose the muscle tissue are known as contractile cells. They originate from mesenchymal cells which differentiate into myoblasts. Myoblasts are embryonic cells which later differentiate into contractile fiber cells. 

FIGURE 2.11 Receptor-occupancy curves for activation of human calcitonin type 2 receptors by the agonist human calcitonin. Ordinates (response as a fraction of the maximal response to human calcitonin). Abscissae (fractional receptor occupancy by human calcitonin). Curves shown for receptors transfected into three cell types human embryonic kidney cells (HEK), Chinese hamster ovary cells (CHO), and Xenopus laevis melanophores. It can be seen that the different cell types lead to differing amplification factors for the conversion from agonist receptor occupancy to tissue response. 

Finally, lentiviral vectors have been shown to transduce human embryonic stem cells. Therefore, this type of gene-therapy vector might also be used in stem cell-based therapies. 

Embryonal carcinoma cell lines have also been established in culture from transplantable teratocarcinomas. The embryonal carcinoma (EC) stem cells present in the tumors actually differentiated, and give rise to a variety of different types of embiyonic and adult cells. When these EC cells are cultured, they still possess the... 

Historically, the development of animal cell culture systems has been dependent upon the development of new types of tissue culture media. Mouse L cells and HeLa cells were developed using a balanced salt solution supplemented with blood plasma, an embryonic tissue extract, and/or serum. In 1955 Eagle developed a nutritionally defined medium, containing all of the essential amino acids, vitamins, cofactors, carbohydrates, salts, and small amounts of dialyzed serum (Table 1). He demonstrated that this minimal essential medium (MEM) supported the long-term growth of mouse L and HeLa ceils. Eagle s MEM was so well defined that the omission of a single essential nutrient eventually resulted in the death of these animal cells in culture. 

Secondary cell cultures, which can be prepared by taking cells from some types of primary culture, usually those derived from embryonic tissue, dispersing them by treatment with trypsin and inoculating some into a fresh batch of medium. A limited number of subcultures can be performed with these sorts of cells, up to a maximum of about 50 before the cells degenerate. 

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