Branching Ratio
Mostrando 13-24 de 30 artigos, teses e dissertações.
-
13. Growth of the bronchial tree in man.
Bronchial tree casts were made from one or both lungs from nine children aged from five weeks to 17 years. The branches of the casts were ordered by the method of Strahler, and diameter ratio, length ratio, and branching ratio were determined. From five to 12 weeks the diameter ratio is about 1.35, but by 13 months it has risen to 1.45, indicating a faster r
-
14. A difference in the composition of bronchial mucus between smokers and non-smokers.
The ratio of the amount of sulphated to sialic acid mucin (Su/Si) in the mucous glands of the human tracheobronchial tree has been investigated in seven smokers and seven non-smokers. The two mucins were studied in histological sections stained by the high iron diamine/Alcian blue pH 2-5 sequence and assessed by a point-counting method. Su/Si was greater in
-
15. Transgenic mice carrying an imbalance in the native ratio of A to B forms of progesterone receptor exhibit developmental abnormalities in mammary glands
In this report we document the creation of transgenic mice in which the native ratio of A and B forms of progesterone receptor (PR) has been altered by the introduction of additional A form as transgene. We also show that in these mice there is an aberration in mammary development. In ovariectomized prepubertal PR-A transgenic mice, end buds with unusual mor
The National Academy of Sciences.
-
16. Motor units in a skeletal muscle of neonatal rat: mechanical properties and weak neuromuscular transmission.
1. Isometric twitch and tetanic tensions were recorded from whole muscles and single motor units in isolated fourth deep lumbrical muscles from neonatal rats (most at 3-5 days old) and from older rats of various ages. 2. Whole-muscle time to peak contraction reduced from about 120 ms at birth to about 20-25 ms at 20 days and older. 3. The number of motor uni
-
17. Chemical mechanisms for cytochrome P-450 hydroxylation: evidence for acylation of heme-bound dioxygen.
Using isotopic tracer methods, we have shown that dihydrolipoic acid (2,3-thioctic acid) acylates the distal oxygen of ferrous oxygenated Pseudomonas cytochrome P-450, forming a transient acyl peroxide intermediate that facilitates oxygen-oxygen bond cleavage. Single-turnover studies with 18O2 indicate one oxygen-18 atom incorporated into the carboxylate gro
-
18. Metabolism of L-fucose and L-rhamnose in Escherichia coli: aerobic-anaerobic regulation of L-lactaldehyde dissimilation.
L-Lactaldehyde is a branching point in the metabolic pathway of L-fucose and L-rhamnose utilization. Under aerobic conditions, L-lactaldehyde is oxidized to L-lactate by the enzyme lactaldehyde dehydrogenase, while under anaerobic conditions, L-lactaldehyde is reduced to L-1,2-propanediol by the enzyme propanediol oxidoreductase. Aerobic growth on either of
-
19. Regional alveolar pressure during periodic flow. Dual manifestations of gas inertia.
We measured pressure excursions at the airway opening and at the alveoli (PA) as well as measured the regional distribution of PA during forced oscillations of six excised dog lungs while frequency (f[2-32 Hz]), tidal volume (VT [5-80 ml]), and mean transpulmonary pressure (PL [25, 10, and 6 cm H2O]) were varied. PA's were measured in four alveolar capsules
-
20. Morphogenesis in Selaginella: Auxin Transport in the Stem 1
Selaginella willdenovii Baker is a prostrate vascular cryptogam with a dorsiventral stem. At each major branching of the stem apex a dorsal and a ventral angle meristem is formed. The ventral meristem becomes determined as a root, and the dorsal meristem as a shoot. The present investigation examined the distribution and transport of 14C-indoleacetic acid th
-
21. Effect of a sputum digestant on the viabiltiy of Mycobacterium fortuitum.
A microcolony technique has been demonstrated as being useful for the rapid determination of the viabilities of single cells of Myocbacterium fortuitum. Cultures of M. fortuitum grown to early logarithmic phase in broth were treated with the sputum digestant N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) for periods of 10 to 40 s. After growth for three ge
-
22. Relationship between sugar chain structure and biological activity of recombinant human erythropoietin produced in Chinese hamster ovary cells.
Two forms of erythropoietin, EPO-bi and EPO-tetra, with different biological activities were isolated from the culture medium of a recombinant Chinese hamster ovary cell line, B8-300, into which the human erythropoietin gene had been introduced. EPO-bi, an unusual form, showed only one-seventh the in vivo activity and 3 times higher in vitro activity of the
-
23. Correlations between the 13C Content of Primary and Secondary Plant Products in Different Cell Compartments and That in Decomposing Basidiomycetes.
Relative carbon isotope ratio ([delta]13C values) of primary and secondary products from different compartments of annual plants, pine needles, wood, and decomposing Basidiomycetes have been determined. An enrichment in 13C was found for storage tissues of annual plants, because of the high level of the primary storage products sucrose and starch; however, t
-
24. Impact of progesterone receptor on cell-fate decisions during mammary gland development
Mammary epithelium contains lineage-limited progenitors that give rise to cells that form distinct morphological structures, ducts vs. lobules, depending on the endocrine status of the female. Progesterone signaling through progesterone receptor (PR) is essential for lobulo-alveolar development that accompanies pregnancy, but not for ductal growth accompanyi
The National Academy of Sciences.