parabiosis

enUK

par·a·bi·o·sis

P0056100 (păr′ə-bī-ō′sĭs)n. pl. par·a·bi·o·ses (-sēz) 1. The natural or surgical union of anatomical parts of two organisms, usually involving exchange of blood, as in the development of conjoined twins or in certain transplant operations.2. A temporary suspension of conductivity or excitability in a nerve.

par′a·bi·ot′ic (-ŏt′ĭk) adj.par′a·bi·ot′i·cal·ly adv.

parabiosis

(ˌpærəbaɪˈəʊsɪs) n1. (Biology) the natural union of two individuals, such as Siamese twins, so that they share a common circulation of the blood2. (Biology) a similar union induced for experimental or therapeutic purposes[C20: from para-¹ + Greek biōsis manner of life, from bios life] parabiotic adj

par•a•bi•o•sis

(ˌpær ə baɪˈoʊ sɪs, -bi-)

n. the physiological or anatomical union of two individuals. [1905–10] par`a•bi•ot′ic (-ˈɒt ɪk) adj.

parabiosis

the uniting of two individual organisms or animals anatomically and physiologically, either under experimental or natural conditions. — parabiotic, adj.See also: Joining

the uniting of two individual organisms or animals anatomically and physiologically, under either experimental or natural conditions. — parabiotic, adj.See also: Biology

Parabiosis

enUK

parabiosis

[¦par·ə·bī′ō·səs] (biology) Experimental joining of two individuals to study the effects of one partner upon the other.

Parabiosis

(1) A phasic reaction of living tissue to a stimulus of specified duration and strength by which the tissue’s excitability, conductivity, and normal processes of excitation are temporarily suppressed. The phenomenon of parabiosis was demonstrated and a theory was developed by N. E. Vvedenskii in 1901 using the neuromuscular system of a frog.

As some stimulus, for example, an electric current, is applied to a nerve a gradually developing, phasic change in the reactive properties of the nerve arises at the site of stimulation. In the first phase—the transformational phase—a weak stimulation of an area of the nerve that is located proximally to the parabiotized area results in roughly the same type of muscle contractions as is the case with strong stimulation. With both strong and weak stimuli, the amplitude of contraction is reduced in comparison with the amplitude that results from a nerve in which no parabiosis has been effected. In the second phase, which is called Paradoxical, strong stimuli to the region that is proximal to the parabiotic region result in weaker tetanic contractions than do weak stimuli. In the third phase—the inhibitory phase—both strong and weak stimuli when applied to an area of the nerve that is located distally to the parabiotic area do not produce any contractions at all. Irreversible changes and atrophy of the nerve result from continued application of the parabiotizing stimulus. When the stimulus is removed, the nerve gradually returns to the initial state through a reverse sequence of the phases of parabiosis.

Parabiosis is accompanied by a permanent decrease in the ability of a nerve to recover after stimulation (seeLABILITY). The excitability and conductivity of a nerve are qualitatively distinct in each phase of parabiosis, which reflects phasic changes in the electrical potential of the stimulated area. Vvedenskii regarded all phases of parabiosis as different manifestations of a single process—excitation. He characterized parabiosis as a stationary type of excitation; he further postulated that parabiosis was the normal form of excitation in the early stages of evolution. D. N. Nasonov and his co-workers showed that the phenomenon of parabiosis can be attributed to reversible changes of cytoplasmic proteins, changes that are similar to the initial phases of protein denaturation. These theories about the mechanism of parabiosis were eventually supported by research on the mechanisms of excitation and inhibition alternation in the central nervous system and by research on higher nervous activity in general.

I. P. Pavlov showed that as internal inhibition in the cerebral cortex arises, a fourth phase of parabiosis is observed—the ultraparadoxical phase. During this phase positive stimuli produce a negative effect, while negative stimuli produce a positive effect. Discovery and elucidation of the phenomenon of parabiosis revealed the genetic unity that underlies the processes of excitation and inhibition and indicated the interconnection between excitability and conductivity.

(2) An experimental method in physiology by which the circulatory and lymphatic systems of two or more organisms are artificially joined. Parabiosis is used in physiological experiments for studying mutual humoral influences between two animals. The technique received widespread acceptance after the work of the German scientists F. Sauerbruch and M. Heyde was publicized in 1908. Parabiosis is also used for studying rejection of tissue and organ transplants and for investigating the action of hormones and other metabolites.

REFERENCES

Ukhtomskii, A., L. Vasil’ev, and M. Vinogradov. Uchenie o parabioze. Moscow, 1927.
Vvedenskii, N. E. “Vozbuzhdenie, tormozhenie i narkoz.” Poln. sobr. soch, vol. 4. Leningrad, 1953.
Nasonov, D. N. Mestnaia reaktsiia protoplazmy i rasprostraniaiushcheesia vozbuzhdenie, 2nd ed. Moscow-Leningrad, 1962.

I. V. ORLOV and V. V. SHERSTNEV

单词	parabiosis
释义	parabiosis enUK par·a·bi·o·sis P0056100 (păr′ə-bī-ō′sĭs)n. pl. par·a·bi·o·ses (-sēz) 1. The natural or surgical union of anatomical parts of two organisms, usually involving exchange of blood, as in the development of conjoined twins or in certain transplant operations.2. A temporary suspension of conductivity or excitability in a nerve. par′a·bi·ot′ic (-ŏt′ĭk) adj.par′a·bi·ot′i·cal·ly adv. parabiosis (ˌpærəbaɪˈəʊsɪs) n1. (Biology) the natural union of two individuals, such as Siamese twins, so that they share a common circulation of the blood2. (Biology) a similar union induced for experimental or therapeutic purposes[C20: from para-¹ + Greek biōsis manner of life, from bios life] parabiotic adj par•a•bi•o•sis (ˌpær ə baɪˈoʊ sɪs, -bi-) n. the physiological or anatomical union of two individuals. [1905–10] par`a•bi•ot′ic (-ˈɒt ɪk) adj. parabiosis the uniting of two individual organisms or animals anatomically and physiologically, either under experimental or natural conditions. — parabiotic, adj.See also: Joining the uniting of two individual organisms or animals anatomically and physiologically, under either experimental or natural conditions. — parabiotic, adj.See also: Biology Parabiosis enUK parabiosis [¦par·ə·bī′ō·səs] (biology) Experimental joining of two individuals to study the effects of one partner upon the other. Parabiosis (1) A phasic reaction of living tissue to a stimulus of specified duration and strength by which the tissue’s excitability, conductivity, and normal processes of excitation are temporarily suppressed. The phenomenon of parabiosis was demonstrated and a theory was developed by N. E. Vvedenskii in 1901 using the neuromuscular system of a frog. As some stimulus, for example, an electric current, is applied to a nerve a gradually developing, phasic change in the reactive properties of the nerve arises at the site of stimulation. In the first phase—the transformational phase—a weak stimulation of an area of the nerve that is located proximally to the parabiotized area results in roughly the same type of muscle contractions as is the case with strong stimulation. With both strong and weak stimuli, the amplitude of contraction is reduced in comparison with the amplitude that results from a nerve in which no parabiosis has been effected. In the second phase, which is called Paradoxical, strong stimuli to the region that is proximal to the parabiotic region result in weaker tetanic contractions than do weak stimuli. In the third phase—the inhibitory phase—both strong and weak stimuli when applied to an area of the nerve that is located distally to the parabiotic area do not produce any contractions at all. Irreversible changes and atrophy of the nerve result from continued application of the parabiotizing stimulus. When the stimulus is removed, the nerve gradually returns to the initial state through a reverse sequence of the phases of parabiosis. Parabiosis is accompanied by a permanent decrease in the ability of a nerve to recover after stimulation (seeLABILITY). The excitability and conductivity of a nerve are qualitatively distinct in each phase of parabiosis, which reflects phasic changes in the electrical potential of the stimulated area. Vvedenskii regarded all phases of parabiosis as different manifestations of a single process—excitation. He characterized parabiosis as a stationary type of excitation; he further postulated that parabiosis was the normal form of excitation in the early stages of evolution. D. N. Nasonov and his co-workers showed that the phenomenon of parabiosis can be attributed to reversible changes of cytoplasmic proteins, changes that are similar to the initial phases of protein denaturation. These theories about the mechanism of parabiosis were eventually supported by research on the mechanisms of excitation and inhibition alternation in the central nervous system and by research on higher nervous activity in general. I. P. Pavlov showed that as internal inhibition in the cerebral cortex arises, a fourth phase of parabiosis is observed—the ultraparadoxical phase. During this phase positive stimuli produce a negative effect, while negative stimuli produce a positive effect. Discovery and elucidation of the phenomenon of parabiosis revealed the genetic unity that underlies the processes of excitation and inhibition and indicated the interconnection between excitability and conductivity. (2) An experimental method in physiology by which the circulatory and lymphatic systems of two or more organisms are artificially joined. Parabiosis is used in physiological experiments for studying mutual humoral influences between two animals. The technique received widespread acceptance after the work of the German scientists F. Sauerbruch and M. Heyde was publicized in 1908. Parabiosis is also used for studying rejection of tissue and organ transplants and for investigating the action of hormones and other metabolites. REFERENCES Ukhtomskii, A., L. Vasil’ev, and M. Vinogradov. Uchenie o parabioze. Moscow, 1927. Vvedenskii, N. E. “Vozbuzhdenie, tormozhenie i narkoz.” Poln. sobr. soch, vol. 4. Leningrad, 1953. Nasonov, D. N. Mestnaia reaktsiia protoplazmy i rasprostraniaiushcheesia vozbuzhdenie, 2nd ed. Moscow-Leningrad, 1962. I. V. ORLOV and V. V. SHERSTNEV parabiosis enUK parabiosis [par″ah-bi-o´sis] 1. the union of two individuals, as conjoined twins, or of experimental animals by surgical operation.2. temporary suppression of conductivity and excitability. adj., adj parabiot´ic. par·a·bi·o·sis (par'ă-bī-ō'sis), 1. Fusion of whole oocytes or embryos, which occurs in some forms of conjoined twins. 2. Surgical joining of the vascular systems of two organisms. [para- + G. biōsis, life] parabiosis (păr′ə-bī-ō′sĭs)n. pl. parabio·ses (-sēz) 1. The natural or surgical union of anatomical parts of two organisms, usually involving exchange of blood, as in the development of conjoined twins or in certain transplant operations.2. A temporary suspension of conductivity or excitability in a nerve. par′a·bi·ot′ic (-ŏt′ĭk) adj.par′a·bi·ot′i·cal·ly adv. par·a·bi·o·sis (par'ă-bī-ō'sis) 1. The fusion of embryos, as occurs in conjoined twins. 2. Surgical joining of the vascular systems of two organisms. [para- + G. biōsis, life] parabiosis the connecting together of two animals in an experiment so as to allow their body fluids to mix. The technique is used, for example, in the study of the role of insect hormones.
随便看	architectural details architectural development team architectural drawing architectural drawings architectural drawings advisory group architectural education architectural element architectural energy corporation architectural engineer architectural engineering architectural engineering and construction management architectural engineering and design management architectural engineering consulting architectural engineering, consulting, operations and maintenance architectural engineering design group, inc. architectural engineering directorate architectural engineering division architectural engineering graduate students association architectural engineering institute architectural-engineering resource center architectural & engineering services architectural evaluation board architectural form definition requirements architectural foundation of los angeles architectural foundation of san francisco