Mechano-chemical regulation of bat wing bones for flight

Regulation of blood flow depends on changes in the sum of arterial (Ra) and venous (Rv) resistances, whereas regulation of capillary pressure (Pc) depends on the ratio of Rv to Ra. If the myogenic response of the arterial system (i.e., delta Ra) is the primary mechanism for controlling pressure and flow when perfusion pressure is lowered, then Pc and total flow should be regulated to the same degree under these conditions. This hypothesis was tested by making direct measurements of Pc and flow in skin and skeletal muscle in the wings of unanesthetized bats. The box method was used to reduce perfusion pressure to the wing. Pressures were measured with a servo-null system; flows were computed from measurements of vascular diameters and red cell velocities using intravital microscopy. All branching orders of arterioles dilated significantly during decreases in box pressure (Pb). For 0 less than Pb less than or equal to -30 mmHg, total flow (1st-order arteriolar flow) remained nearly constant, whereas Pc was "regulated" only approximately 60%. These results cannot be explained by changes in arteriolar resistance alone and suggest that changes in Rv may be important. The possible consequences of flow redistribution, capillary recruitment, and micropressure sampling procedures are discussed in relationship to local regulation of capillary pressure and flow.

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Bat wing or butterfly sign: Pulmonary oedema

Journal of Medical Imaging and Radiation Oncology ◽

10.1111/1754-9485.06_12785 ◽

2018 ◽

Vol 62 ◽

pp. 18-18

Author(s):

Jason Han ◽

Hao Xiang ◽

William E Ridley ◽

Lloyd J Ridley

Keyword(s):

Pulmonary Oedema ◽

Bat Wing

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Organ Regeneration on Excised Roots of Chondrilla Juncea and Its Chemical Regulation

Australian Journal of Biological Sciences ◽

10.1071/bi9720691 ◽

1972 ◽

Vol 25 (4) ◽

pp. 691 ◽

Cited By ~ 17

Author(s):

NP Kefford ◽

OH Caso

Keyword(s):

Root Formation ◽

Bud Formation ◽

Endogenous Factors ◽

Chemical Regulation ◽

Synthetic Auxins ◽

Organ Regeneration ◽

Low Concentrations ◽

Standard Assay ◽

Gibberellin Treatment ◽

Regulation Of Regeneration

The effects of endogenous factors (plant age, section length, and section location) and environmental factors (temperature and mineral nutrition) upon organ regeneration on isolated root sections of Ohondrilla juncea L. were used to develop a standard assay system for the study of the chemical regulation of regeneration. Bud and root formation and its polarity in the presence of a variety of regulators alone and in combinations were observed quantitatively. Bud numbers were increased by auxin (low concentrations), cytokinin, and gibberellin treatments. High concentra� tions of auxin inhibited bud formation and this effect was reversed by antiauxin, cytokinin, or gibberellin. Adenine did not counteract auxin� induced bud inhibition but adenine and N�6�benzyladenine did counteract inhibition induced by the purine antagonist 2,6�diaminopurine. Numbers of regenerated roots were increased by auxin treatment and reduced by cytokinin and gibberellin treatment. On control and auxin� treated sections, bud formation was strongly polar and proximal and cytokinin and gibberellin treatments lessened the polarity. Growth retardants inhibited regeneration. Of a number of synthetic auxins tested, 2,4.dichlorophenoxy. acet.O.methylhydroxamic acid and 4�amino.3,5,6.trichloropicolinic acid were the most effective inhibitors of bud formation.

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